diff --git a/src/game/bossfile.c b/src/game/bossfile.c
index 98f4f4413..2fd46a41a 100644
--- a/src/game/bossfile.c
+++ b/src/game/bossfile.c
@@ -58,34 +58,34 @@ void func0f1106f4(u8 *dst)
 	bcopy(var800a22d0, dst, sizeof(var800a22d0));
 }
 
-u32 func0f110720(void)
+u32 bossfileFindFileId(void)
 {
 	struct pakfileheader header;
-	u32 sp3c[513];
-	u32 sp38 = 0;
+	u32 fileids[513];
+	u32 candidate = 0;
 	s32 i;
 
-	if (pakGetFileIdsByType(SAVEDEVICE_GAMEPAK, PAKFILETYPE_BOSS, sp3c) == 0) {
-		for (i = 0; sp3c[i] != 0; i++) {
-			pakFindFile(SAVEDEVICE_GAMEPAK, sp3c[i], &header);
+	if (pakGetFileIdsByType(SAVEDEVICE_GAMEPAK, PAKFILETYPE_BOSS, fileids) == 0) {
+		for (i = 0; fileids[i] != 0; i++) {
+			pakFindFile(SAVEDEVICE_GAMEPAK, fileids[i], &header);
 
 			if (!header.occupied) {
-				sp38 = sp3c[i];
+				candidate = fileids[i];
 				break;
 			}
 		}
 
-		for (i = 0; sp3c[i] != 0; i++) {
-			pakFindFile(SAVEDEVICE_GAMEPAK, sp3c[i], &header);
+		for (i = 0; fileids[i] != 0; i++) {
+			pakFindFile(SAVEDEVICE_GAMEPAK, fileids[i], &header);
 
 			if (header.occupied) {
-				sp38 = sp3c[i];
+				candidate = fileids[i];
 				break;
 			}
 		}
 	}
 
-	return sp38;
+	return candidate;
 }
 
 void bossfileLoad(void)
@@ -93,17 +93,17 @@ void bossfileLoad(void)
 	bool failed = false;
 	struct savebuffer buffer;
 	s32 i;
-	s32 tmp;
+	s32 fileid;
 	struct fileguid guid;
 
-	tmp = func0f110720();
+	fileid = bossfileFindFileId();
 
-	if (tmp == 0) {
+	if (fileid == 0) {
 		failed = true;
 	} else {
 		savebufferClear(&buffer);
 
-		if (pak0f116800(SAVEDEVICE_GAMEPAK, tmp, buffer.bytes, 0)) {
+		if (pakReadBodyAtGuid(SAVEDEVICE_GAMEPAK, fileid, buffer.bytes, 0) != 0) {
 			failed = true;
 		}
 	}
@@ -156,7 +156,7 @@ void bossfileSave(void)
 	struct fileguid guid;
 	u32 stack;
 	s32 i;
-	s32 tmp;
+	s32 fileid;
 
 	savebufferClear(&buffer);
 
@@ -188,13 +188,13 @@ void bossfileSave(void)
 
 	func0f0d54c4(&buffer);
 
-	tmp = func0f110720();
+	fileid = bossfileFindFileId();
 
-	if (tmp == 0) {
+	if (fileid == 0) {
 		faultAssert("fileGuid", "bossfile.c", PAL ? 377 : 375);
 	}
 
-	if (pak0f116828(SAVEDEVICE_GAMEPAK, tmp, PAKFILETYPE_BOSS, buffer.bytes, NULL, 0)) {
+	if (pakSaveAtGuid(SAVEDEVICE_GAMEPAK, fileid, PAKFILETYPE_BOSS, buffer.bytes, NULL, 0) != 0) {
 		sp12c = true;
 	}
 }
diff --git a/src/game/camdraw.c b/src/game/camdraw.c
index 9707e363f..764ee69d9 100644
--- a/src/game/camdraw.c
+++ b/src/game/camdraw.c
@@ -7803,7 +7803,7 @@ glabel func0f15015c
 /*  f150178:	afb1001c */ 	sw	$s1,0x1c($sp)
 /*  f15017c:	afb00018 */ 	sw	$s0,0x18($sp)
 /*  f150180:	27a60040 */ 	addiu	$a2,$sp,0x40
-/*  f150184:	0fc45a00 */ 	jal	pak0f116800
+/*  f150184:	0fc45a00 */ 	jal	pakReadBodyAtGuid
 /*  f150188:	24070080 */ 	addiu	$a3,$zero,0x80
 /*  f15018c:	1440000b */ 	bnez	$v0,.L0f1501bc
 /*  f150190:	8fa504e8 */ 	lw	$a1,0x4e8($sp)
@@ -7866,7 +7866,7 @@ glabel func0f15015c
 /*  f150258:	83a404e3 */ 	lb	$a0,0x4e3($sp)
 /*  f15025c:	8fa504e4 */ 	lw	$a1,0x4e4($sp)
 /*  f150260:	27a60038 */ 	addiu	$a2,$sp,0x38
-/*  f150264:	0fc45a00 */ 	jal	pak0f116800
+/*  f150264:	0fc45a00 */ 	jal	pakReadBodyAtGuid
 /*  f150268:	00003825 */ 	or	$a3,$zero,$zero
 /*  f15026c:	14400076 */ 	bnez	$v0,.L0f150448
 /*  f150270:	00401825 */ 	or	$v1,$v0,$zero
@@ -7995,8 +7995,8 @@ glabel func0f15015c
 /*  f150440:	10000004 */ 	b	.L0f150454
 /*  f150444:	24020001 */ 	addiu	$v0,$zero,0x1
 .L0f150448:
-/*  f150448:	3c01800a */ 	lui	$at,%hi(var800a21f8)
-/*  f15044c:	ac2321f8 */ 	sw	$v1,%lo(var800a21f8)($at)
+/*  f150448:	3c01800a */ 	lui	$at,%hi(g_FilemgrLastPakError)
+/*  f15044c:	ac2321f8 */ 	sw	$v1,%lo(g_FilemgrLastPakError)($at)
 /*  f150450:	00001025 */ 	or	$v0,$zero,$zero
 .L0f150454:
 /*  f150454:	8fbf001c */ 	lw	$ra,0x1c($sp)
@@ -8182,7 +8182,7 @@ glabel func0f15015c
 /*  f1506f8:	02402825 */ 	or	$a1,$s2,$zero
 /*  f1506fc:	24060008 */ 	addiu	$a2,$zero,0x8
 /*  f150700:	27a71050 */ 	addiu	$a3,$sp,0x1050
-/*  f150704:	0fc45a0a */ 	jal	pak0f116828
+/*  f150704:	0fc45a0a */ 	jal	pakSaveAtGuid
 /*  f150708:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f15070c:	1440001f */ 	bnez	$v0,.L0f15078c
 /*  f150710:	00401825 */ 	or	$v1,$v0,$zero
@@ -8220,8 +8220,8 @@ glabel func0f15015c
 /*  f150784:	10000004 */ 	b	.L0f150798
 /*  f150788:	ae2903f8 */ 	sw	$t1,0x3f8($s1)
 .L0f15078c:
-/*  f15078c:	3c01800a */ 	lui	$at,%hi(var800a21f8)
-/*  f150790:	ac2321f8 */ 	sw	$v1,%lo(var800a21f8)($at)
+/*  f15078c:	3c01800a */ 	lui	$at,%hi(g_FilemgrLastPakError)
+/*  f150790:	ac2321f8 */ 	sw	$v1,%lo(g_FilemgrLastPakError)($at)
 /*  f150794:	2402ffff */ 	addiu	$v0,$zero,-1
 .L0f150798:
 /*  f150798:	8fbf002c */ 	lw	$ra,0x2c($sp)
diff --git a/src/game/filelist.c b/src/game/filelist.c
index ad464b8f1..1426d74e7 100644
--- a/src/game/filelist.c
+++ b/src/game/filelist.c
@@ -183,7 +183,7 @@ void filelistUpdate(struct filelist *list)
 	s8 filedevices[2560];
 	s32 i;
 	s32 j;
-	s32 maybepfserr;
+	s32 ret;
 	s32 len;
 
 	// Display order means game pak then controller paks
@@ -208,9 +208,9 @@ void filelistUpdate(struct filelist *list)
 		list->unk305[dis2dev[i]] = 0;
 		list->devicestartindexes[i] = -1;
 
-		maybepfserr = pakGetFileIdsByType(dis2dev[i], sp3a88[list->filetype], spa88);
+		ret = pakGetFileIdsByType(dis2dev[i], sp3a88[list->filetype], spa88);
 
-		if (maybepfserr == 0) {
+		if (ret == 0) {
 			// No error
 			for (j = 0; spa88[j] != 0; j++) {
 				sp1288[len] = spa88[j];
@@ -230,7 +230,7 @@ void filelistUpdate(struct filelist *list)
 			// PFS error?
 			list->spacesfree[dis2dev[i]] = -1;
 
-			if (maybepfserr == 13) {
+			if (ret == 13) {
 				list->timeuntilupdate = 5;
 			}
 		}
@@ -243,11 +243,11 @@ void filelistUpdate(struct filelist *list)
 	// Iterating files
 	for (i = 0; i < len; i++) {
 		struct filelistfile *file = &list->files[list->numfiles];
-		s32 maybepfserr = pak0f116800(filedevices[i], sp1288[i], file->name, sizeof(file->name));
+		s32 ret = pakReadBodyAtGuid(filedevices[i], sp1288[i], file->name, sizeof(file->name));
 
-		if (maybepfserr);
+		if (ret);
 
-		if (maybepfserr == 0) {
+		if (ret == 0) {
 			// No error
 			if (list->devicestartindexes[dev2dis[filedevices[i]]] == -1) {
 				list->numdevices++;
@@ -258,7 +258,7 @@ void filelistUpdate(struct filelist *list)
 			file->fileid = sp1288[i];
 
 			list->numfiles++;
-		} else if (maybepfserr == 10) {
+		} else if (ret == 10) {
 			// PFS_ERR_ID_FATAL?
 			list->unk305[filedevices[i]]++;
 
diff --git a/src/game/filemgr.c b/src/game/filemgr.c
index 74488e585..3213b567d 100644
--- a/src/game/filemgr.c
+++ b/src/game/filemgr.c
@@ -23,7 +23,7 @@
 struct fileguid g_FilemgrFileToCopy;
 struct fileguid var800a21e8;
 struct fileguid g_FilemgrFileToDelete;
-struct fileguid var800a21f8;
+s32 g_FilemgrLastPakError;
 struct gamefile g_GameFile;
 u32 var800a22bc;
 struct fileguid g_GameFileGuid;
@@ -720,8 +720,14 @@ bool filemgrAttemptOperation(s32 device, bool closeonsuccess)
 	s32 errno = 0;
 	bool showfilesaved = (g_Menus[g_MpPlayerNum].fm.isretryingsave & 1) != 0;
 
-	const s32 sp30[] = {0x80, 0x40, 0x20, 0x08};
-	s32 sp2c;
+	const s32 filetypes[] = {
+		PAKFILETYPE_GAME,
+		PAKFILETYPE_MPSETUP,
+		PAKFILETYPE_MPPLAYER,
+		PAKFILETYPE_008,
+	};
+
+	s32 newfileid;
 
 	switch (g_Menus[g_MpPlayerNum].fm.fileop) {
 	case FILEOP_SAVE_GAME_002:
@@ -748,12 +754,12 @@ bool filemgrAttemptOperation(s32 device, bool closeonsuccess)
 	case FILEOP_WRITE_GAME:
 	case FILEOP_WRITE_MPSETUP:
 	case FILEOP_WRITE_MPPLAYER:
-		sp2c = 0;
+		newfileid = 0;
 		func0f0d5690(g_Menus[g_MpPlayerNum].fm.unke44, g_Menus[g_MpPlayerNum].fm.filename);
-		errno = pak0f116828(device,
+		errno = pakSaveAtGuid(device,
 				g_Menus[g_MpPlayerNum].fm.fileid,
-				sp30[g_Menus[g_MpPlayerNum].fm.fileop - 6],
-				g_Menus[g_MpPlayerNum].fm.unke44, &sp2c, 0);
+				filetypes[g_Menus[g_MpPlayerNum].fm.fileop - 6],
+				g_Menus[g_MpPlayerNum].fm.unke44, &newfileid, NULL);
 		var80075bd0[g_Menus[g_MpPlayerNum].fm.fileop - 6] = 1;
 		break;
 	case FILEOP_LOAD_GAME:
@@ -774,7 +780,7 @@ bool filemgrAttemptOperation(s32 device, bool closeonsuccess)
 	case FILEOP_READ_GAME:
 	case FILEOP_READ_MPSETUP:
 	case FILEOP_READ_MPPLAYER:
-		errno = pak0f116800(device,
+		errno = pakReadBodyAtGuid(device,
 				g_Menus[g_MpPlayerNum].fm.fileid,
 				g_Menus[g_MpPlayerNum].fm.unke44, 0);
 		break;
@@ -927,7 +933,7 @@ glabel var7f1ad424nb
 /*  f104bd4:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f104bd8:	83a4004b */ 	lb	$a0,0x4b($sp)
 /*  f104bdc:	8c450da4 */ 	lw	$a1,0xda4($v0)
-/*  f104be0:	0fc442fb */ 	jal	pak0f116828
+/*  f104be0:	0fc442fb */ 	jal	pakSaveAtGuid
 /*  f104be4:	8c470da0 */ 	lw	$a3,0xda0($v0)
 /*  f104be8:	3c188007 */ 	lui	$t8,0x8007
 /*  f104bec:	8f183af0 */ 	lw	$t8,0x3af0($t8)
@@ -971,7 +977,7 @@ glabel var7f1ad424nb
 /*  f104c84:	8ce7d088 */ 	lw	$a3,-0x2f78($a3)
 /*  f104c88:	83a4004b */ 	lb	$a0,0x4b($sp)
 /*  f104c8c:	8c450da4 */ 	lw	$a1,0xda4($v0)
-/*  f104c90:	0fc442f1 */ 	jal	pak0f116800
+/*  f104c90:	0fc442f1 */ 	jal	pakReadBodyAtGuid
 /*  f104c94:	8c460da0 */ 	lw	$a2,0xda0($v0)
 /*  f104c98:	00403025 */ 	or	$a2,$v0,$zero
 .NB0f104c9c:
@@ -1068,7 +1074,7 @@ bool filemgrSaveOrLoad(struct fileguid *guid, s32 fileop, u32 playernum)
 		g_Menus[g_MpPlayerNum].fm.fileop = fileop;
 		g_Menus[g_MpPlayerNum].fm.mpplayernum = playernum;
 		g_Menus[g_MpPlayerNum].fm.isretryingsave = 0;
-		var800a21f8.fileid = 0;
+		g_FilemgrLastPakError = 0;
 	}
 
 	g_Menus[g_MpPlayerNum].fm.fileid = guid->fileid;
diff --git a/src/game/gamefile.c b/src/game/gamefile.c
index cf75c0a2c..e9b3bfac1 100644
--- a/src/game/gamefile.c
+++ b/src/game/gamefile.c
@@ -900,7 +900,7 @@ s32 gamefileLoad(s32 device)
 	s32 i;
 	s32 j;
 	struct savebuffer buffer;
-	s32 tmp;
+	s32 ret;
 	u32 stack;
 
 	p1index = g_Vars.coopplayernum >= 0 || g_Vars.antiplayernum >= 0 ? 0 : 4;
@@ -908,10 +908,10 @@ s32 gamefileLoad(s32 device)
 
 	if (device >= 0) {
 		savebufferClear(&buffer);
-		tmp = pak0f116800(device, g_GameFileGuid.fileid, buffer.bytes, 0);
-		var800a21f8.fileid = tmp;
+		ret = pakReadBodyAtGuid(device, g_GameFileGuid.fileid, buffer.bytes, 0);
+		g_FilemgrLastPakError = ret;
 
-		if (tmp == 0) {
+		if (ret == 0) {
 			cheatsDisableAll();
 			savebufferReadString(&buffer, g_GameFile.name, 0);
 			g_GameFile.thumbnail = savebufferReadBits(&buffer, 5);
@@ -1001,8 +1001,8 @@ s32 gamefileLoad(s32 device)
 s32 gamefileSave(s32 device, s32 fileid, u16 deviceserial)
 {
 	u32 stack;
-	s32 sp140;
-	s32 tmp;
+	s32 newfileid;
+	s32 ret;
 	s32 i;
 	s32 j;
 	s32 p1index;
@@ -1133,11 +1133,11 @@ s32 gamefileSave(s32 device, s32 fileid, u16 deviceserial)
 
 		func0f0d54c4(&buffer);
 
-		tmp = pak0f116828(device, fileid, PAKFILETYPE_GAME, buffer.bytes, &sp140, 0);
-		var800a21f8.fileid = tmp;
+		ret = pakSaveAtGuid(device, fileid, PAKFILETYPE_GAME, buffer.bytes, &newfileid, 0);
+		g_FilemgrLastPakError = ret;
 
-		if (tmp == 0) {
-			g_GameFileGuid.fileid = sp140;
+		if (ret == 0) {
+			g_GameFileGuid.fileid = newfileid;
 			g_GameFileGuid.deviceserial = deviceserial;
 
 			return 0;
diff --git a/src/game/mplayer/mplayer.c b/src/game/mplayer/mplayer.c
index 4a161e94a..140a031f0 100644
--- a/src/game/mplayer/mplayer.c
+++ b/src/game/mplayer/mplayer.c
@@ -8759,10 +8759,10 @@ void mpplayerfileGetOverview(char *arg0, char *name, u32 *playtime)
 	*playtime = savebufferReadBits(&buffer, 28);
 }
 
-s32 mpplayerfileSave(s32 playernum, s32 device, s32 arg2, u16 deviceserial)
+s32 mpplayerfileSave(s32 playernum, s32 device, s32 fileid, u16 deviceserial)
 {
-	s32 tmp;
-	s32 fileid;
+	s32 ret;
+	s32 newfileid;
 	struct savebuffer buffer;
 
 	if (device >= 0) {
@@ -8772,15 +8772,15 @@ s32 mpplayerfileSave(s32 playernum, s32 device, s32 arg2, u16 deviceserial)
 
 		var80075bd0[2] = true;
 
-		tmp = pak0f116828(device, arg2, PAKFILETYPE_MPPLAYER, buffer.bytes, &fileid, 0);
+		ret = pakSaveAtGuid(device, fileid, PAKFILETYPE_MPPLAYER, buffer.bytes, &newfileid, 0);
 
-		if (tmp == 0) {
-			g_MpPlayers[playernum].fileguid.fileid = fileid;
+		if (ret == 0) {
+			g_MpPlayers[playernum].fileguid.fileid = newfileid;
 			g_MpPlayers[playernum].fileguid.deviceserial = deviceserial;
 			return 0;
 		}
 
-		var800a21f8.fileid = tmp;
+		g_FilemgrLastPakError = ret;
 		return -1;
 	}
 
@@ -8789,15 +8789,15 @@ s32 mpplayerfileSave(s32 playernum, s32 device, s32 arg2, u16 deviceserial)
 
 s32 mpplayerfileLoad(s32 playernum, s32 device, s32 fileid, u16 deviceserial)
 {
-	s32 tmp;
+	s32 ret;
 	struct savebuffer buffer;
 
 	if (device >= 0) {
 		savebufferClear(&buffer);
 
-		tmp = pak0f116800(device, fileid, buffer.bytes, 0);
+		ret = pakReadBodyAtGuid(device, fileid, buffer.bytes, 0);
 
-		if (tmp == 0) {
+		if (ret == 0) {
 			g_MpPlayers[playernum].fileguid.fileid = fileid;
 			g_MpPlayers[playernum].fileguid.deviceserial = deviceserial;
 
@@ -8808,7 +8808,7 @@ s32 mpplayerfileLoad(s32 playernum, s32 device, s32 fileid, u16 deviceserial)
 			return 0;
 		}
 
-		var800a21f8.fileid = tmp;
+		g_FilemgrLastPakError = ret;
 		return -1;
 	}
 
@@ -9459,8 +9459,8 @@ void mpsetupfileGetOverview(char *arg0, char *filename, u16 *numsims, u16 *stage
 
 s32 mpsetupfileSave(s32 device, s32 fileid, u16 deviceserial)
 {
-	s32 tmp;
-	s32 sp100;
+	s32 ret;
+	s32 newfileid;
 	struct savebuffer buffer;
 
 	if (device >= 0) {
@@ -9468,16 +9468,16 @@ s32 mpsetupfileSave(s32 device, s32 fileid, u16 deviceserial)
 		mpsetupfileSaveWad(&buffer);
 		func0f0d54c4(&buffer);
 
-		tmp = pak0f116828(device, fileid, PAKFILETYPE_MPSETUP, buffer.bytes, &sp100, 0);
+		ret = pakSaveAtGuid(device, fileid, PAKFILETYPE_MPSETUP, buffer.bytes, &newfileid, 0);
 		var80075bd0[1] = true;
 
-		if (tmp == 0) {
-			g_MpSetup.fileguid.fileid = sp100;
+		if (ret == 0) {
+			g_MpSetup.fileguid.fileid = newfileid;
 			g_MpSetup.fileguid.deviceserial = deviceserial;
 			return 0;
 		}
 
-		var800a21f8.fileid = tmp;
+		g_FilemgrLastPakError = ret;
 		return -1;
 	}
 
@@ -9486,14 +9486,14 @@ s32 mpsetupfileSave(s32 device, s32 fileid, u16 deviceserial)
 
 s32 mpsetupfileLoad(s32 device, s32 fileid, u16 deviceserial)
 {
-	s32 tmp;
+	s32 ret;
 	struct savebuffer buffer;
 
 	if (device >= 0) {
 		savebufferClear(&buffer);
-		tmp = pak0f116800(device, fileid, buffer.bytes, 0);
+		ret = pakReadBodyAtGuid(device, fileid, buffer.bytes, 0);
 
-		if (tmp == 0) {
+		if (ret == 0) {
 			g_MpSetup.fileguid.fileid = fileid;
 			g_MpSetup.fileguid.deviceserial = deviceserial;
 
@@ -9503,7 +9503,7 @@ s32 mpsetupfileLoad(s32 device, s32 fileid, u16 deviceserial)
 			return 0;
 		}
 
-		var800a21f8.fileid = tmp;
+		g_FilemgrLastPakError = ret;
 
 		return -1;
 	}
diff --git a/src/game/pak/pak.c b/src/game/pak/pak.c
index 7edfd5354..735ab5ef0 100644
--- a/src/game/pak/pak.c
+++ b/src/game/pak/pak.c
@@ -274,14 +274,14 @@ s32 pak0f1167d8(s8 device)
 	return pak0f119298(device);
 }
 
-s32 pak0f116800(s8 device, s32 fileid, u8 *body, s32 arg3)
+s32 pakReadBodyAtGuid(s8 device, s32 fileid, u8 *body, s32 arg3)
 {
-	return pak0f118bc8(device, fileid, body, arg3);
+	return _pakReadBodyAtGuid(device, fileid, body, arg3);
 }
 
-s32 pak0f116828(s8 device, s32 fileid, s32 filetype, u8 *body, s32 *outfileid, s32 arg5)
+s32 pakSaveAtGuid(s8 device, s32 fileid, s32 filetype, u8 *body, s32 *outfileid, u8 *olddata)
 {
-	return pak0f11789c(device, fileid, filetype, body, outfileid, arg5);
+	return _pakSaveAtGuid(device, fileid, filetype, body, outfileid, olddata);
 }
 
 bool pakDeleteFile(s8 device, s32 fileid)
@@ -519,7 +519,7 @@ s32 _pakDeleteFile(s8 device, s32 fileid)
 		return 1;
 	}
 
-	result = pakWriteFile(device, result, header.filetype, NULL, 0, NULL, NULL, 0, header.unk0c_21 + 1);
+	result = pakWriteFileAtOffset(device, result, header.filetype, NULL, 0, NULL, NULL, 0, header.generation + 1);
 
 	if (result) {
 		return result;
@@ -538,7 +538,7 @@ s32 _pakDeleteFile(s8 device, s32 fileid)
 		return 3;
 	}
 
-	result = pakWriteFile(device, tmp, header.filetype, NULL, 0, NULL, NULL, 0, header.unk0c_21 + 1);
+	result = pakWriteFileAtOffset(device, tmp, header.filetype, NULL, 0, NULL, NULL, 0, header.generation + 1);
 
 	if (result) {
 		return result;
@@ -884,343 +884,131 @@ void pakDumpEeprom(void)
 	pakDumpBuffer(buffer, 2048, "EEPROM DUMP");
 }
 
-const char var7f1b3be8[] = "PakSaveAtGuid: new guid = %x\n";
+/**
+ * Overwrite the save file which has the specified fileid. This is typically an
+ * earlier version of the same logical save file. A new fileid will be generated
+ * and returned to *outfileid.
+ *
+ * The function doesn't literally overwrite the old file. On the pak, there is
+ * a swap file reserved for atomic writes. The new file is written into the
+ * swap file, then the old file is marked as swap.
+ */
+s32 _pakSaveAtGuid(s8 device, s32 fileid, s32 filetype, u8 *newdata, s32 *outfileid, u8 *olddataptr)
+{
+	struct pakfileheader header;
+	struct pakfileheader swapheader;
+	s32 result;
+	s32 oldoffset;
+	s32 i;
+	s32 swapoffset;
+	u32 fileids[1024];
+	s32 swapfileid = 0;
+	u8 olddata[0x800];
+
+	// Find the file to be "replaced"
+	oldoffset = pakFindFile(device, fileid, &header);
+
+	if (oldoffset && (!oldoffset || oldoffset >= pakGetNumBytes(device) || (pakGetBlockSize(device) - 1 & oldoffset))) {
+		return 3;
+	}
+
+	if (filetype != header.filetype) {
+		return 12;
+	}
+
+	// Find all files on the pak of the same filetype,
+	// then iterate them to find the swap file
+	pakGetFileIdsByType(device, header.filetype, fileids);
+
+	// NTSC Beta initialises swapoffset to -1 so it can detect if the loop below
+	// has been entered. But in NTSC 1.0 they realised that pakFindFile can
+	// return -1, so they initialised the variable to 0xeeeeeeee instead and
+	// added the check for -1 in the loop below.
+#if VERSION >= VERSION_NTSC_1_0
+	swapoffset = 0xeeeeeeee;
+#else
+	swapoffset = -1;
+#endif
+
+	for (i = 0; fileids[i] != 0; i++) {
+		swapoffset = pakFindFile(device, fileids[i], &swapheader);
 
 #if VERSION >= VERSION_NTSC_1_0
-GLOBAL_ASM(
-glabel pak0f11789c
-/*  f11789c:	27bde780 */ 	addiu	$sp,$sp,-6272
-/*  f1178a0:	afb10034 */ 	sw	$s1,0x34($sp)
-/*  f1178a4:	00048e00 */ 	sll	$s1,$a0,0x18
-/*  f1178a8:	00117603 */ 	sra	$t6,$s1,0x18
-/*  f1178ac:	afa41880 */ 	sw	$a0,0x1880($sp)
-/*  f1178b0:	000e2600 */ 	sll	$a0,$t6,0x18
-/*  f1178b4:	afbf003c */ 	sw	$ra,0x3c($sp)
-/*  f1178b8:	afb20038 */ 	sw	$s2,0x38($sp)
-/*  f1178bc:	afa61888 */ 	sw	$a2,0x1888($sp)
-/*  f1178c0:	00047e03 */ 	sra	$t7,$a0,0x18
-/*  f1178c4:	00a09025 */ 	or	$s2,$a1,$zero
-/*  f1178c8:	01c08825 */ 	or	$s1,$t6,$zero
-/*  f1178cc:	afb00030 */ 	sw	$s0,0x30($sp)
-/*  f1178d0:	afa7188c */ 	sw	$a3,0x188c($sp)
-/*  f1178d4:	afa0084c */ 	sw	$zero,0x84c($sp)
-/*  f1178d8:	01e02025 */ 	or	$a0,$t7,$zero
-/*  f1178dc:	0fc464da */ 	jal	pakFindFile
-/*  f1178e0:	27a61870 */ 	addiu	$a2,$sp,0x1870
-/*  f1178e4:	10400015 */ 	beqz	$v0,.L0f11793c
-/*  f1178e8:	afa21858 */ 	sw	$v0,0x1858($sp)
-/*  f1178ec:	10400011 */ 	beqz	$v0,.L0f117934
-/*  f1178f0:	00112600 */ 	sll	$a0,$s1,0x18
-/*  f1178f4:	0004c603 */ 	sra	$t8,$a0,0x18
-/*  f1178f8:	0fc45ff0 */ 	jal	pakGetNumBytes
-/*  f1178fc:	03002025 */ 	or	$a0,$t8,$zero
-/*  f117900:	8fb91858 */ 	lw	$t9,0x1858($sp)
-/*  f117904:	00112600 */ 	sll	$a0,$s1,0x18
-/*  f117908:	00044603 */ 	sra	$t0,$a0,0x18
-/*  f11790c:	0322082b */ 	sltu	$at,$t9,$v0
-/*  f117910:	10200008 */ 	beqz	$at,.L0f117934
-/*  f117914:	00000000 */ 	sll	$zero,$zero,0x0
-/*  f117918:	0fc45974 */ 	jal	pakGetBlockSize
-/*  f11791c:	01002025 */ 	or	$a0,$t0,$zero
-/*  f117920:	8faa1858 */ 	lw	$t2,0x1858($sp)
-/*  f117924:	2449ffff */ 	addiu	$t1,$v0,-1
-/*  f117928:	012a5824 */ 	and	$t3,$t1,$t2
-/*  f11792c:	51600004 */ 	beqzl	$t3,.L0f117940
-/*  f117930:	8fa51878 */ 	lw	$a1,0x1878($sp)
-.L0f117934:
-/*  f117934:	1000006d */ 	beqz	$zero,.L0f117aec
-/*  f117938:	24020003 */ 	addiu	$v0,$zero,0x3
-.L0f11793c:
-/*  f11793c:	8fa51878 */ 	lw	$a1,0x1878($sp)
-.L0f117940:
-/*  f117940:	8fad1888 */ 	lw	$t5,0x1888($sp)
-/*  f117944:	00112600 */ 	sll	$a0,$s1,0x18
-/*  f117948:	000565c2 */ 	srl	$t4,$a1,0x17
-/*  f11794c:	11ac0003 */ 	beq	$t5,$t4,.L0f11795c
-/*  f117950:	01802825 */ 	or	$a1,$t4,$zero
-/*  f117954:	10000065 */ 	beqz	$zero,.L0f117aec
-/*  f117958:	2402000c */ 	addiu	$v0,$zero,0xc
-.L0f11795c:
-/*  f11795c:	00047603 */ 	sra	$t6,$a0,0x18
-/*  f117960:	01c02025 */ 	or	$a0,$t6,$zero
-/*  f117964:	0fc459ec */ 	jal	pakGetFileIdsByType
-/*  f117968:	27a60850 */ 	addiu	$a2,$sp,0x850
-/*  f11796c:	8faf0850 */ 	lw	$t7,0x850($sp)
-/*  f117970:	3c10eeee */ 	lui	$s0,0xeeee
-/*  f117974:	3610eeee */ 	ori	$s0,$s0,0xeeee
-/*  f117978:	11e0001b */ 	beqz	$t7,.L0f1179e8
-/*  f11797c:	27a30850 */ 	addiu	$v1,$sp,0x850
-/*  f117980:	8c650000 */ 	lw	$a1,0x0($v1)
-/*  f117984:	00112600 */ 	sll	$a0,$s1,0x18
-.L0f117988:
-/*  f117988:	0004ce03 */ 	sra	$t9,$a0,0x18
-/*  f11798c:	03202025 */ 	or	$a0,$t9,$zero
-/*  f117990:	27a61860 */ 	addiu	$a2,$sp,0x1860
-/*  f117994:	0fc464da */ 	jal	pakFindFile
-/*  f117998:	afa30048 */ 	sw	$v1,0x48($sp)
-/*  f11799c:	2401ffff */ 	addiu	$at,$zero,-1
-/*  f1179a0:	8fa30048 */ 	lw	$v1,0x48($sp)
-/*  f1179a4:	14410003 */ 	bne	$v0,$at,.L0f1179b4
-/*  f1179a8:	00408025 */ 	or	$s0,$v0,$zero
-/*  f1179ac:	1000004f */ 	beqz	$zero,.L0f117aec
-/*  f1179b0:	24020001 */ 	addiu	$v0,$zero,0x1
-.L0f1179b4:
-/*  f1179b4:	8fa4186c */ 	lw	$a0,0x186c($sp)
-/*  f1179b8:	00044f40 */ 	sll	$t1,$a0,0x1d
-/*  f1179bc:	05200006 */ 	bltz	$t1,.L0f1179d8
-/*  f1179c0:	00041340 */ 	sll	$v0,$a0,0xd
-/*  f1179c4:	00025642 */ 	srl	$t2,$v0,0x19
-/*  f1179c8:	524a0004 */ 	beql	$s2,$t2,.L0f1179dc
-/*  f1179cc:	8c650004 */ 	lw	$a1,0x4($v1)
-/*  f1179d0:	10000005 */ 	beqz	$zero,.L0f1179e8
-/*  f1179d4:	afaa084c */ 	sw	$t2,0x84c($sp)
-.L0f1179d8:
-/*  f1179d8:	8c650004 */ 	lw	$a1,0x4($v1)
-.L0f1179dc:
-/*  f1179dc:	24630004 */ 	addiu	$v1,$v1,0x4
-/*  f1179e0:	54a0ffe9 */ 	bnezl	$a1,.L0f117988
-/*  f1179e4:	00112600 */ 	sll	$a0,$s1,0x18
-.L0f1179e8:
-/*  f1179e8:	24010004 */ 	addiu	$at,$zero,0x4
-/*  f1179ec:	16210011 */ 	bne	$s1,$at,.L0f117a34
-/*  f1179f0:	00112600 */ 	sll	$a0,$s1,0x18
-/*  f1179f4:	00045e03 */ 	sra	$t3,$a0,0x18
-/*  f1179f8:	01602025 */ 	or	$a0,$t3,$zero
-/*  f1179fc:	8fa5084c */ 	lw	$a1,0x84c($sp)
-/*  f117a00:	27a6004c */ 	addiu	$a2,$sp,0x4c
-/*  f117a04:	0fc45a00 */ 	jal	pak0f116800
-/*  f117a08:	2407ffff */ 	addiu	$a3,$zero,-1
-/*  f117a0c:	14400003 */ 	bnez	$v0,.L0f117a1c
-/*  f117a10:	27a3004c */ 	addiu	$v1,$sp,0x4c
-/*  f117a14:	10000007 */ 	beqz	$zero,.L0f117a34
-/*  f117a18:	afa31894 */ 	sw	$v1,0x1894($sp)
-.L0f117a1c:
-/*  f117a1c:	2401000a */ 	addiu	$at,$zero,0xa
-/*  f117a20:	54410004 */ 	bnel	$v0,$at,.L0f117a34
-/*  f117a24:	afa01894 */ 	sw	$zero,0x1894($sp)
-/*  f117a28:	10000002 */ 	beqz	$zero,.L0f117a34
-/*  f117a2c:	afa31894 */ 	sw	$v1,0x1894($sp)
-/*  f117a30:	afa01894 */ 	sw	$zero,0x1894($sp)
-.L0f117a34:
-/*  f117a34:	8faf187c */ 	lw	$t7,0x187c($sp)
-/*  f117a38:	8fad1890 */ 	lw	$t5,0x1890($sp)
-/*  f117a3c:	8fae1894 */ 	lw	$t6,0x1894($sp)
-/*  f117a40:	000fc500 */ 	sll	$t8,$t7,0x14
-/*  f117a44:	0018cdc2 */ 	srl	$t9,$t8,0x17
-/*  f117a48:	00112600 */ 	sll	$a0,$s1,0x18
-/*  f117a4c:	00046603 */ 	sra	$t4,$a0,0x18
-/*  f117a50:	27280001 */ 	addiu	$t0,$t9,0x1
-/*  f117a54:	afa80020 */ 	sw	$t0,0x20($sp)
-/*  f117a58:	01802025 */ 	or	$a0,$t4,$zero
-/*  f117a5c:	02002825 */ 	or	$a1,$s0,$zero
-/*  f117a60:	8fa61888 */ 	lw	$a2,0x1888($sp)
-/*  f117a64:	8fa7188c */ 	lw	$a3,0x188c($sp)
-/*  f117a68:	afa00010 */ 	sw	$zero,0x10($sp)
-/*  f117a6c:	afb2001c */ 	sw	$s2,0x1c($sp)
-/*  f117a70:	afad0014 */ 	sw	$t5,0x14($sp)
-/*  f117a74:	0fc46f15 */ 	jal	pakWriteFile
-/*  f117a78:	afae0018 */ 	sw	$t6,0x18($sp)
-/*  f117a7c:	10400003 */ 	beqz	$v0,.L0f117a8c
-/*  f117a80:	8fa51858 */ 	lw	$a1,0x1858($sp)
-/*  f117a84:	10000019 */ 	beqz	$zero,.L0f117aec
-/*  f117a88:	24020004 */ 	addiu	$v0,$zero,0x4
-.L0f117a8c:
-/*  f117a8c:	2401ffff */ 	addiu	$at,$zero,-1
-/*  f117a90:	54a10004 */ 	bnel	$a1,$at,.L0f117aa4
-/*  f117a94:	3c01eeee */ 	lui	$at,0xeeee
-/*  f117a98:	10000014 */ 	beqz	$zero,.L0f117aec
-/*  f117a9c:	24020001 */ 	addiu	$v0,$zero,0x1
-/*  f117aa0:	3c01eeee */ 	lui	$at,0xeeee
-.L0f117aa4:
-/*  f117aa4:	3421eeee */ 	ori	$at,$at,0xeeee
-/*  f117aa8:	10a1000f */ 	beq	$a1,$at,.L0f117ae8
-/*  f117aac:	00112600 */ 	sll	$a0,$s1,0x18
-/*  f117ab0:	8fab187c */ 	lw	$t3,0x187c($sp)
-/*  f117ab4:	8faa084c */ 	lw	$t2,0x84c($sp)
-/*  f117ab8:	00044e03 */ 	sra	$t1,$a0,0x18
-/*  f117abc:	000b6500 */ 	sll	$t4,$t3,0x14
-/*  f117ac0:	000c6dc2 */ 	srl	$t5,$t4,0x17
-/*  f117ac4:	afad0020 */ 	sw	$t5,0x20($sp)
-/*  f117ac8:	01202025 */ 	or	$a0,$t1,$zero
-/*  f117acc:	8fa61888 */ 	lw	$a2,0x1888($sp)
-/*  f117ad0:	00003825 */ 	or	$a3,$zero,$zero
-/*  f117ad4:	afa00010 */ 	sw	$zero,0x10($sp)
-/*  f117ad8:	afa00014 */ 	sw	$zero,0x14($sp)
-/*  f117adc:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f117ae0:	0fc46f15 */ 	jal	pakWriteFile
-/*  f117ae4:	afaa001c */ 	sw	$t2,0x1c($sp)
-.L0f117ae8:
-/*  f117ae8:	00001025 */ 	or	$v0,$zero,$zero
-.L0f117aec:
-/*  f117aec:	8fbf003c */ 	lw	$ra,0x3c($sp)
-/*  f117af0:	8fb00030 */ 	lw	$s0,0x30($sp)
-/*  f117af4:	8fb10034 */ 	lw	$s1,0x34($sp)
-/*  f117af8:	8fb20038 */ 	lw	$s2,0x38($sp)
-/*  f117afc:	03e00008 */ 	jr	$ra
-/*  f117b00:	27bd1880 */ 	addiu	$sp,$sp,0x1880
-);
-#else
-GLOBAL_ASM(
-glabel pak0f11789c
-/*  f111c00:	27bde780 */ 	addiu	$sp,$sp,-6272
-/*  f111c04:	afb20034 */ 	sw	$s2,0x34($sp)
-/*  f111c08:	00049600 */ 	sll	$s2,$a0,0x18
-/*  f111c0c:	00127603 */ 	sra	$t6,$s2,0x18
-/*  f111c10:	afa41880 */ 	sw	$a0,0x1880($sp)
-/*  f111c14:	000e2600 */ 	sll	$a0,$t6,0x18
-/*  f111c18:	afbf003c */ 	sw	$ra,0x3c($sp)
-/*  f111c1c:	afb30038 */ 	sw	$s3,0x38($sp)
-/*  f111c20:	afa61888 */ 	sw	$a2,0x1888($sp)
-/*  f111c24:	00047e03 */ 	sra	$t7,$a0,0x18
-/*  f111c28:	00a09825 */ 	or	$s3,$a1,$zero
-/*  f111c2c:	01c09025 */ 	or	$s2,$t6,$zero
-/*  f111c30:	afb10030 */ 	sw	$s1,0x30($sp)
-/*  f111c34:	afb0002c */ 	sw	$s0,0x2c($sp)
-/*  f111c38:	afa7188c */ 	sw	$a3,0x188c($sp)
-/*  f111c3c:	afa0084c */ 	sw	$zero,0x84c($sp)
-/*  f111c40:	01e02025 */ 	or	$a0,$t7,$zero
-/*  f111c44:	0fc44da7 */ 	jal	pakFindFile
-/*  f111c48:	27a61870 */ 	addiu	$a2,$sp,0x1870
-/*  f111c4c:	10400015 */ 	beqz	$v0,.NB0f111ca4
-/*  f111c50:	afa21858 */ 	sw	$v0,0x1858($sp)
-/*  f111c54:	10400011 */ 	beqz	$v0,.NB0f111c9c
-/*  f111c58:	00122600 */ 	sll	$a0,$s2,0x18
-/*  f111c5c:	0004c603 */ 	sra	$t8,$a0,0x18
-/*  f111c60:	0fc448fb */ 	jal	pakGetNumBytes
-/*  f111c64:	03002025 */ 	or	$a0,$t8,$zero
-/*  f111c68:	8fb91858 */ 	lw	$t9,0x1858($sp)
-/*  f111c6c:	00122600 */ 	sll	$a0,$s2,0x18
-/*  f111c70:	00044603 */ 	sra	$t0,$a0,0x18
-/*  f111c74:	0322082b */ 	sltu	$at,$t9,$v0
-/*  f111c78:	10200008 */ 	beqz	$at,.NB0f111c9c
-/*  f111c7c:	00000000 */ 	sll	$zero,$zero,0x0
-/*  f111c80:	0fc4428c */ 	jal	pakGetBlockSize
-/*  f111c84:	01002025 */ 	or	$a0,$t0,$zero
-/*  f111c88:	8faa1858 */ 	lw	$t2,0x1858($sp)
-/*  f111c8c:	2449ffff */ 	addiu	$t1,$v0,-1
-/*  f111c90:	012a5824 */ 	and	$t3,$t1,$t2
-/*  f111c94:	51600004 */ 	beqzl	$t3,.NB0f111ca8
-/*  f111c98:	8fa51878 */ 	lw	$a1,0x1878($sp)
-.NB0f111c9c:
-/*  f111c9c:	1000005f */ 	beqz	$zero,.NB0f111e1c
-/*  f111ca0:	24020003 */ 	addiu	$v0,$zero,0x3
-.NB0f111ca4:
-/*  f111ca4:	8fa51878 */ 	lw	$a1,0x1878($sp)
-.NB0f111ca8:
-/*  f111ca8:	8fad1888 */ 	lw	$t5,0x1888($sp)
-/*  f111cac:	00122600 */ 	sll	$a0,$s2,0x18
-/*  f111cb0:	000565c2 */ 	srl	$t4,$a1,0x17
-/*  f111cb4:	11ac0003 */ 	beq	$t5,$t4,.NB0f111cc4
-/*  f111cb8:	01802825 */ 	or	$a1,$t4,$zero
-/*  f111cbc:	10000057 */ 	beqz	$zero,.NB0f111e1c
-/*  f111cc0:	2402000c */ 	addiu	$v0,$zero,0xc
-.NB0f111cc4:
-/*  f111cc4:	00047603 */ 	sra	$t6,$a0,0x18
-/*  f111cc8:	01c02025 */ 	or	$a0,$t6,$zero
-/*  f111ccc:	0fc442dd */ 	jal	pakGetFileIdsByType
-/*  f111cd0:	27a60850 */ 	addiu	$a2,$sp,0x850
-/*  f111cd4:	8faf0850 */ 	lw	$t7,0x850($sp)
-/*  f111cd8:	2411ffff */ 	addiu	$s1,$zero,-1
-/*  f111cdc:	27b00850 */ 	addiu	$s0,$sp,0x850
-/*  f111ce0:	51e00016 */ 	beqzl	$t7,.NB0f111d3c
-/*  f111ce4:	24010004 */ 	addiu	$at,$zero,0x4
-/*  f111ce8:	8e050000 */ 	lw	$a1,0x0($s0)
-/*  f111cec:	00122600 */ 	sll	$a0,$s2,0x18
-.NB0f111cf0:
-/*  f111cf0:	0004ce03 */ 	sra	$t9,$a0,0x18
-/*  f111cf4:	03202025 */ 	or	$a0,$t9,$zero
-/*  f111cf8:	0fc44da7 */ 	jal	pakFindFile
-/*  f111cfc:	27a61860 */ 	addiu	$a2,$sp,0x1860
-/*  f111d00:	8fa3186c */ 	lw	$v1,0x186c($sp)
-/*  f111d04:	00408825 */ 	or	$s1,$v0,$zero
-/*  f111d08:	00034f40 */ 	sll	$t1,$v1,0x1d
-/*  f111d0c:	05200006 */ 	bltz	$t1,.NB0f111d28
-/*  f111d10:	00031340 */ 	sll	$v0,$v1,0xd
-/*  f111d14:	00025642 */ 	srl	$t2,$v0,0x19
-/*  f111d18:	526a0004 */ 	beql	$s3,$t2,.NB0f111d2c
-/*  f111d1c:	8e050004 */ 	lw	$a1,0x4($s0)
-/*  f111d20:	10000005 */ 	beqz	$zero,.NB0f111d38
-/*  f111d24:	afaa084c */ 	sw	$t2,0x84c($sp)
-.NB0f111d28:
-/*  f111d28:	8e050004 */ 	lw	$a1,0x4($s0)
-.NB0f111d2c:
-/*  f111d2c:	26100004 */ 	addiu	$s0,$s0,0x4
-/*  f111d30:	54a0ffef */ 	bnezl	$a1,.NB0f111cf0
-/*  f111d34:	00122600 */ 	sll	$a0,$s2,0x18
-.NB0f111d38:
-/*  f111d38:	24010004 */ 	addiu	$at,$zero,0x4
-.NB0f111d3c:
-/*  f111d3c:	1641000f */ 	bne	$s2,$at,.NB0f111d7c
-/*  f111d40:	27b0004c */ 	addiu	$s0,$sp,0x4c
-/*  f111d44:	00122600 */ 	sll	$a0,$s2,0x18
-/*  f111d48:	00045e03 */ 	sra	$t3,$a0,0x18
-/*  f111d4c:	01602025 */ 	or	$a0,$t3,$zero
-/*  f111d50:	8fa5084c */ 	lw	$a1,0x84c($sp)
-/*  f111d54:	02003025 */ 	or	$a2,$s0,$zero
-/*  f111d58:	0fc442f1 */ 	jal	pak0f116800
-/*  f111d5c:	2407ffff */ 	addiu	$a3,$zero,-1
-/*  f111d60:	10400003 */ 	beqz	$v0,.NB0f111d70
-/*  f111d64:	2401000a */ 	addiu	$at,$zero,0xa
-/*  f111d68:	54410004 */ 	bnel	$v0,$at,.NB0f111d7c
-/*  f111d6c:	afa01894 */ 	sw	$zero,0x1894($sp)
-.NB0f111d70:
-/*  f111d70:	10000002 */ 	beqz	$zero,.NB0f111d7c
-/*  f111d74:	afb01894 */ 	sw	$s0,0x1894($sp)
-/*  f111d78:	afa01894 */ 	sw	$zero,0x1894($sp)
-.NB0f111d7c:
-/*  f111d7c:	8fae187c */ 	lw	$t6,0x187c($sp)
-/*  f111d80:	8fb01890 */ 	lw	$s0,0x1890($sp)
-/*  f111d84:	8fad1894 */ 	lw	$t5,0x1894($sp)
-/*  f111d88:	000e7d00 */ 	sll	$t7,$t6,0x14
-/*  f111d8c:	000fc5c2 */ 	srl	$t8,$t7,0x17
-/*  f111d90:	00122600 */ 	sll	$a0,$s2,0x18
-/*  f111d94:	00046603 */ 	sra	$t4,$a0,0x18
-/*  f111d98:	27190001 */ 	addiu	$t9,$t8,0x1
-/*  f111d9c:	afb90020 */ 	sw	$t9,0x20($sp)
-/*  f111da0:	01802025 */ 	or	$a0,$t4,$zero
-/*  f111da4:	02202825 */ 	or	$a1,$s1,$zero
-/*  f111da8:	8fa61888 */ 	lw	$a2,0x1888($sp)
-/*  f111dac:	8fa7188c */ 	lw	$a3,0x188c($sp)
-/*  f111db0:	afa00010 */ 	sw	$zero,0x10($sp)
-/*  f111db4:	afb3001c */ 	sw	$s3,0x1c($sp)
-/*  f111db8:	afb00014 */ 	sw	$s0,0x14($sp)
-/*  f111dbc:	0fc456f6 */ 	jal	pakWriteFile
-/*  f111dc0:	afad0018 */ 	sw	$t5,0x18($sp)
-/*  f111dc4:	10400003 */ 	beqz	$v0,.NB0f111dd4
-/*  f111dc8:	8fa51858 */ 	lw	$a1,0x1858($sp)
-/*  f111dcc:	10000013 */ 	beqz	$zero,.NB0f111e1c
-/*  f111dd0:	24020004 */ 	addiu	$v0,$zero,0x4
-.NB0f111dd4:
-/*  f111dd4:	2401ffff */ 	addiu	$at,$zero,-1
-/*  f111dd8:	10a1000f */ 	beq	$a1,$at,.NB0f111e18
-/*  f111ddc:	00122600 */ 	sll	$a0,$s2,0x18
-/*  f111de0:	8faa187c */ 	lw	$t2,0x187c($sp)
-/*  f111de4:	8fa9084c */ 	lw	$t1,0x84c($sp)
-/*  f111de8:	00044603 */ 	sra	$t0,$a0,0x18
-/*  f111dec:	000a5d00 */ 	sll	$t3,$t2,0x14
-/*  f111df0:	000b65c2 */ 	srl	$t4,$t3,0x17
-/*  f111df4:	afac0020 */ 	sw	$t4,0x20($sp)
-/*  f111df8:	01002025 */ 	or	$a0,$t0,$zero
-/*  f111dfc:	8fa61888 */ 	lw	$a2,0x1888($sp)
-/*  f111e00:	00003825 */ 	or	$a3,$zero,$zero
-/*  f111e04:	afa00010 */ 	sw	$zero,0x10($sp)
-/*  f111e08:	afa00014 */ 	sw	$zero,0x14($sp)
-/*  f111e0c:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f111e10:	0fc456f6 */ 	jal	pakWriteFile
-/*  f111e14:	afa9001c */ 	sw	$t1,0x1c($sp)
-.NB0f111e18:
-/*  f111e18:	00001025 */ 	or	$v0,$zero,$zero
-.NB0f111e1c:
-/*  f111e1c:	8fbf003c */ 	lw	$ra,0x3c($sp)
-/*  f111e20:	8fb0002c */ 	lw	$s0,0x2c($sp)
-/*  f111e24:	8fb10030 */ 	lw	$s1,0x30($sp)
-/*  f111e28:	8fb20034 */ 	lw	$s2,0x34($sp)
-/*  f111e2c:	8fb30038 */ 	lw	$s3,0x38($sp)
-/*  f111e30:	03e00008 */ 	jr	$ra
-/*  f111e34:	27bd1880 */ 	addiu	$sp,$sp,0x1880
-);
+		if (swapoffset == -1) {
+			return 1;
+		}
 #endif
 
+		if (!swapheader.occupied && swapheader.fileid != fileid) {
+			// Found the swap file
+			swapfileid = swapheader.fileid;
+			break;
+		}
+	}
+
+	// For the game pak, don't trust the olddataptr argument and instead
+	// populate it by loading the data at the swap file (olddataptr is used to
+	// skip writes if any old and new blocks are matching).
+	// @bug? Shouldn't this also apply to controller paks? How would the caller
+	// know which swap space was going to be used? Maybe controller paks don't
+	// use the olddataptr optimisation?
+	if (device == SAVEDEVICE_GAMEPAK) {
+		result = pakReadBodyAtGuid(device, swapfileid, olddata, -1);
+
+		// NTSC 1.0 just writes the same thing a different way
+#if VERSION >= VERSION_NTSC_1_0
+		if (result == 0) {
+			olddataptr = olddata;
+		} else if (result == 10) {
+			olddataptr = olddata;
+		} else {
+			olddataptr = NULL;
+		}
+#else
+		if (result == 0 || result == 10) {
+			olddataptr = olddata;
+		} else {
+			olddataptr = NULL;
+		}
+#endif
+	}
+
+	// Write the new file into the swap space
+	result = pakWriteFileAtOffset(device, swapoffset, filetype, newdata, 0, outfileid, olddataptr, fileid, header.generation + 1);
+
+	if (result != PAKERROR_OK) {
+		return 4;
+	}
+
+	if (outfileid) {
+		osSyncPrintf("PakSaveAtGuid: new guid = %x\n", outfileid);
+	}
+
+	// NTSC Beta skips marking the old file as vacant if the file wasn't found
+	// and returns an OK value. NTSC Final makes it return an error instead.
+	// @bug: The 0xeeeeeeee check should have been done earlier for swapoffset
+	// instead. As it turns out, if swap space wasn't found then
+	// pakWriteFileAtOffset would have returned an error above and this function
+	// would have returned before this check occurs. And oldoffset will never be
+	// 0xeeeeeeee (even with 4GB of storage) because 0xeeeeeeee is not aligned
+	// to a 16-byte boundary. So this bug is harmless.
+#if VERSION >= VERSION_NTSC_1_0
+	if (oldoffset == -1) {
+		return 1;
+	}
+
+	if (oldoffset != 0xeeeeeeee) {
+		pakWriteFileAtOffset(device, oldoffset, filetype, NULL, 0, NULL, NULL, swapfileid, header.generation);
+	}
+#else
+	if (oldoffset != -1) {
+		pakWriteFileAtOffset(device, oldoffset, filetype, NULL, 0, NULL, NULL, swapfileid, header.generation);
+	}
+#endif
+
+	return 0;
+}
+
 #if VERSION >= VERSION_NTSC_1_0
 s32 pakInitPak(OSMesgQueue *mq, OSPfs *pfs, s32 channel, s32 *arg3)
 #else
@@ -1830,7 +1618,7 @@ glabel pak0f118674
 /*  f118888:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f11888c:	afa00018 */ 	sw	$zero,0x18($sp)
 /*  f118890:	afa0001c */ 	sw	$zero,0x1c($sp)
-/*  f118894:	0fc46f15 */ 	jal	pakWriteFile
+/*  f118894:	0fc46f15 */ 	jal	pakWriteFileAtOffset
 /*  f118898:	afad0014 */ 	sw	$t5,0x14($sp)
 /*  f11889c:	14400033 */ 	bnez	$v0,.L0f11896c
 /*  f1188a0:	8faf0054 */ 	lw	$t7,0x54($sp)
@@ -1879,7 +1667,7 @@ glabel pak0f118674
 /*  f118940:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f118944:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f118948:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f11894c:	0fc46f15 */ 	jal	pakWriteFile
+/*  f11894c:	0fc46f15 */ 	jal	pakWriteFileAtOffset
 /*  f118950:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f118954:	14400003 */ 	bnez	$v0,.L0f118964
 /*  f118958:	00000000 */ 	sll	$zero,$zero,0x0
@@ -2063,7 +1851,7 @@ glabel pak0f118674
 /*  f118870:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f118874:	afa00018 */ 	sw	$zero,0x18($sp)
 /*  f118878:	afa0001c */ 	sw	$zero,0x1c($sp)
-/*  f11887c:	0fc46e75 */ 	jal	pakWriteFile
+/*  f11887c:	0fc46e75 */ 	jal	pakWriteFileAtOffset
 /*  f118880:	afaa0014 */ 	sw	$t2,0x14($sp)
 /*  f118884:	14400023 */ 	bnez	$v0,.L0f118914
 /*  f118888:	8fac0050 */ 	lw	$t4,0x50($sp)
@@ -2094,7 +1882,7 @@ glabel pak0f118674
 /*  f1188e8:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f1188ec:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f1188f0:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f1188f4:	0fc46e75 */ 	jal	pakWriteFile
+/*  f1188f4:	0fc46e75 */ 	jal	pakWriteFileAtOffset
 /*  f1188f8:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f1188fc:	14400003 */ 	bnez	$v0,.L0f11890c
 /*  f118900:	00000000 */ 	sll	$zero,$zero,0x0
@@ -2263,7 +2051,7 @@ glabel pak0f118674
 /*  f112c24:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f112c28:	afa00018 */ 	sw	$zero,0x18($sp)
 /*  f112c2c:	afa0001c */ 	sw	$zero,0x1c($sp)
-/*  f112c30:	0fc456f6 */ 	jal	pakWriteFile
+/*  f112c30:	0fc456f6 */ 	jal	pakWriteFileAtOffset
 /*  f112c34:	afb90014 */ 	sw	$t9,0x14($sp)
 /*  f112c38:	14400023 */ 	bnez	$v0,.NB0f112cc8
 /*  f112c3c:	8fa90050 */ 	lw	$t1,0x50($sp)
@@ -2294,7 +2082,7 @@ glabel pak0f118674
 /*  f112c9c:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f112ca0:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f112ca4:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f112ca8:	0fc456f6 */ 	jal	pakWriteFile
+/*  f112ca8:	0fc456f6 */ 	jal	pakWriteFileAtOffset
 /*  f112cac:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f112cb0:	14400003 */ 	bnez	$v0,.NB0f112cc0
 /*  f112cb4:	00000000 */ 	sll	$zero,$zero,0x0
@@ -2406,7 +2194,7 @@ glabel pak0f118674
 //		}
 //
 //		// 86c
-//		if (pakWriteFile(device, sp96, filetype, NULL, 0, olddata, NULL, 0, 1) == 0) {
+//		if (pakWriteFileAtOffset(device, sp96, filetype, NULL, 0, olddata, NULL, 0, 1) == 0) {
 //#if VERSION >= VERSION_NTSC_FINAL
 //			// 8a4
 //			if (sp84) {
@@ -2428,7 +2216,7 @@ glabel pak0f118674
 //			// 8f4
 //			sp96 += pakGetAlignedFileLenByBodyLen(device, pakGetBodyLenByType(device, filetype));
 //
-//			if (pakWriteFile(device, sp96, PAKFILETYPE_TERMINATOR, NULL, 0, NULL, NULL, 0, 1) == 0) {
+//			if (pakWriteFileAtOffset(device, sp96, PAKFILETYPE_TERMINATOR, NULL, 0, NULL, NULL, 0, 1) == 0) {
 //				return 0;
 //			}
 //
@@ -2627,7 +2415,7 @@ s32 pak0f118b04(s8 device, u32 fileid)
 	return 0;
 }
 
-s32 pak0f118bc8(s8 device, s32 fileid, u8 *body, s32 arg3)
+s32 _pakReadBodyAtGuid(s8 device, s32 fileid, u8 *body, s32 arg3)
 {
 	s32 offset;
 	struct pakfileheader header;
@@ -3418,7 +3206,7 @@ glabel pakFindFile
 #if VERSION >= VERSION_NTSC_FINAL
 bool pakWriteBlankFile(u32 device, u32 offset, struct pakfileheader *header)
 {
-	if (pakWriteFile(device, offset, PAKFILETYPE_BLANK, NULL, pakGetBodyLenByFileLen(header->filelen), NULL, NULL, 0, 1) == 0) {
+	if (pakWriteFileAtOffset(device, offset, PAKFILETYPE_BLANK, NULL, pakGetBodyLenByFileLen(header->filelen), NULL, NULL, 0, 1) == 0) {
 		return true;
 	}
 
@@ -3533,7 +3321,7 @@ glabel pakRepairAsBlank
 /*  f119658:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f11965c:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f119660:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f119664:	0fc46f15 */ 	jal	pakWriteFile
+/*  f119664:	0fc46f15 */ 	jal	pakWriteFileAtOffset
 /*  f119668:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f11966c:	1000001b */ 	beqz	$zero,.L0f1196dc
 /*  f119670:	24020001 */ 	addiu	$v0,$zero,0x1
@@ -3555,7 +3343,7 @@ glabel pakRepairAsBlank
 /*  f1196a8:	afa20010 */ 	sw	$v0,0x10($sp)
 /*  f1196ac:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f1196b0:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f1196b4:	0fc46f15 */ 	jal	pakWriteFile
+/*  f1196b4:	0fc46f15 */ 	jal	pakWriteFileAtOffset
 /*  f1196b8:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f1196bc:	10400005 */ 	beqz	$v0,.L0f1196d4
 /*  f1196c0:	8fae0094 */ 	lw	$t6,0x94($sp)
@@ -3658,7 +3446,7 @@ bool pakRepairAsBlank(s8 device, u32 *offsetptr, struct pakfileheader *header)
 
 		// If the end was reached, write a terminator at the starting offset
 		if (offset >= g_Paks[device].numbytes) {
-			pakWriteFile(device, start, PAKFILETYPE_TERMINATOR, NULL, 0, NULL, NULL, 0, 1);
+			pakWriteFileAtOffset(device, start, PAKFILETYPE_TERMINATOR, NULL, 0, NULL, NULL, 0, 1);
 			return true;
 		}
 #elif VERSION >= VERSION_NTSC_1_0
@@ -3712,7 +3500,7 @@ bool pakRepairAsBlank(s8 device, u32 *offsetptr, struct pakfileheader *header)
 	osSyncPrintf("Pak %d -> Pak_RepairAsBlank - St=%u, Ed=%u, Gap=%u, Blank Size=%u\n", device, start, offset, offset - start, bodylen);
 
 	// Write the blank file ranging from to the start to the current offset
-	result = pakWriteFile(device, start, PAKFILETYPE_BLANK, NULL, bodylen, NULL, NULL, 0, 1);
+	result = pakWriteFileAtOffset(device, start, PAKFILETYPE_BLANK, NULL, bodylen, NULL, NULL, 0, 1);
 
 	if (result != 0) {
 		osSyncPrintf("Pak %d -> Pak_RepairAsBlank - Fatal Error at tOffset %u\n", device, offset);
@@ -3830,7 +3618,7 @@ glabel pak0f11970c
 /*  f11a318:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f11a31c:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f11a320:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f11a324:	0fc471d4 */ 	jal	pakWriteFile
+/*  f11a324:	0fc471d4 */ 	jal	pakWriteFileAtOffset
 /*  f11a328:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f11a32c:	50400082 */ 	beqzl	$v0,.PF0f11a538
 /*  f11a330:	8fae07a4 */ 	lw	$t6,0x7a4($sp)
@@ -4306,7 +4094,7 @@ glabel pak0f11970c
 /*  f119838:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f11983c:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f119840:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f119844:	0fc46f15 */ 	jal	pakWriteFile
+/*  f119844:	0fc46f15 */ 	jal	pakWriteFileAtOffset
 /*  f119848:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f11984c:	50400082 */ 	beqzl	$v0,.L0f119a58
 /*  f119850:	8fae07a4 */ 	lw	$t6,0x7a4($sp)
@@ -4784,7 +4572,7 @@ glabel pak0f11970c
 /*  f119734:	afa00010 */ 	sw	$zero,0x10($sp)
 /*  f119738:	afa00014 */ 	sw	$zero,0x14($sp)
 /*  f11973c:	afa00018 */ 	sw	$zero,0x18($sp)
-/*  f119740:	0fc46e75 */ 	jal	pakWriteFile
+/*  f119740:	0fc46e75 */ 	jal	pakWriteFileAtOffset
 /*  f119744:	afa0001c */ 	sw	$zero,0x1c($sp)
 /*  f119748:	50400080 */ 	beqzl	$v0,.L0f11994c
 /*  f11974c:	8fac047c */ 	lw	$t4,0x47c($sp)
@@ -5795,7 +5583,7 @@ void pakMergeBlanks(s8 device)
 			if (mergestartoffset != 0xffff) {
 				u32 filelen = offset - mergestartoffset + header.filelen - sizeof(struct pakfileheader);
 
-				if (pakWriteFile(device, mergestartoffset, PAKFILETYPE_BLANK, NULL, filelen, NULL, NULL, 0, 1) != PAKERROR_OK) {
+				if (pakWriteFileAtOffset(device, mergestartoffset, PAKFILETYPE_BLANK, NULL, filelen, NULL, NULL, 0, 1) != PAKERROR_OK) {
 					osSyncPrintf("> Pak_DefragPak_Level1 - Merge of two blanks failed");
 				}
 
@@ -7911,7 +7699,7 @@ s32 pakScrub(s8 device)
 #endif
 	g_Paks[device].headercachecount = 0;
 
-	pakWriteFile(device, 0, PAKFILETYPE_TERMINATOR, NULL, 0, NULL, NULL, 0, 1);
+	pakWriteFileAtOffset(device, 0, PAKFILETYPE_TERMINATOR, NULL, 0, NULL, NULL, 0, 1);
 
 	result = pakReadWriteBlock(device, PFS(device), g_Paks[device].noteindex, PFS_WRITE, address, pakGetBlockSize(device), data);
 
@@ -8479,7 +8267,7 @@ bool pakReplaceFileAtOffsetWithBlank(s8 device, u32 offset)
 	result = pakReadHeaderAtOffset(device, offset, &header);
 
 	if (result == 0) {
-		result = pakWriteFile(device, offset, PAKFILETYPE_BLANK, NULL, header.filelen - sizeof(struct pakfileheader), NULL, NULL, 0, 1);
+		result = pakWriteFileAtOffset(device, offset, PAKFILETYPE_BLANK, NULL, header.filelen - sizeof(struct pakfileheader), NULL, NULL, 0, 1);
 
 		if (result == 0) {
 			return true;
@@ -8491,7 +8279,7 @@ bool pakReplaceFileAtOffsetWithBlank(s8 device, u32 offset)
 
 #if VERSION >= VERSION_NTSC_1_0
 GLOBAL_ASM(
-glabel pakWriteFile
+glabel pakWriteFileAtOffset
 /*  f11bc54:	27bddf40 */ 	addiu	$sp,$sp,-8384
 /*  f11bc58:	afb70044 */ 	sw	$s7,0x44($sp)
 /*  f11bc5c:	0004be00 */ 	sll	$s7,$a0,0x18
@@ -8942,7 +8730,7 @@ glabel pakWriteFile
 );
 #else
 GLOBAL_ASM(
-glabel pakWriteFile
+glabel pakWriteFileAtOffset
 /*  f115bd8:	27bddf40 */ 	addiu	$sp,$sp,-8384
 /*  f115bdc:	afb70044 */ 	sw	$s7,0x44($sp)
 /*  f115be0:	0004be00 */ 	sll	$s7,$a0,0x18
@@ -9395,7 +9183,7 @@ glabel pakWriteFile
 const char var7f1b45e4[] = "-forceversion";
 
 // Mismatch: callee-save registers are handled differently
-//s32 pakWriteFile(s8 device, u32 offset, s32 filetype, u8 *newdata, s32 bodylenarg, s32 *outfileid, u8 *olddata, u32 fileid, u32 arg8)
+//s32 pakWriteFileAtOffset(s8 device, u32 offset, s32 filetype, u8 *newdata, s32 bodylenarg, s32 *outfileid, u8 *olddata, u32 fileid, u32 generation)
 //{
 //	u8 header[sizeof(struct pakfileheader)]; // 20b0
 //	struct pakfileheader *headerptr;
@@ -9417,7 +9205,7 @@ const char var7f1b45e4[] = "-forceversion";
 //
 //	blocksize = pakGetBlockSize(device);
 //
-//	arg8 &= 0x1ff;
+//	generation &= 0x1ff;
 //	bodylen = bodylenarg ? bodylenarg : pakGetBodyLenByType(device, filetype);
 //	filelen = pakGetAlignedFileLenByBodyLen(device, bodylen);
 //
@@ -9432,7 +9220,7 @@ const char var7f1b45e4[] = "-forceversion";
 //
 //	headerptr->version = version;
 //	headerptr->bodylen = bodylen;
-//	headerptr->unk0c_21 = arg8;
+//	headerptr->generation = generation;
 //	headerptr->filetype = filetype;
 //	headerptr->fileid &= 0x7f;
 //
diff --git a/src/include/bss.h b/src/include/bss.h
index 6863f40d5..c43e6892a 100644
--- a/src/include/bss.h
+++ b/src/include/bss.h
@@ -197,7 +197,7 @@ extern u32 g_CheatsActiveBank0;
 extern u32 g_CheatsActiveBank1;
 extern u32 g_CheatsEnabledBank0;
 extern u32 g_CheatsEnabledBank1;
-extern struct fileguid var800a21f8;
+extern s32 g_FilemgrLastPakError;
 extern struct gamefile g_GameFile;
 extern struct fileguid g_GameFileGuid;
 extern s8 g_AltTitleUnlocked;
diff --git a/src/include/game/bossfile.h b/src/include/game/bossfile.h
index d88226de9..6ee68a317 100644
--- a/src/include/game/bossfile.h
+++ b/src/include/game/bossfile.h
@@ -5,7 +5,7 @@
 #include "types.h"
 
 bool bossfileLoadFull(void);
-u32 func0f110720(void);
+u32 bossfileFindFileId(void);
 void bossfileLoad(void);
 void bossfileSave(void);
 void bossfileSetDefaults(void);
diff --git a/src/include/game/mplayer/mplayer.h b/src/include/game/mplayer/mplayer.h
index b0143b8cc..815694f83 100644
--- a/src/include/game/mplayer/mplayer.h
+++ b/src/include/game/mplayer/mplayer.h
@@ -102,7 +102,7 @@ void mpplayerfileSaveGunFuncs(struct savebuffer *buffer, s32 playernum);
 void mpplayerfileLoadWad(s32 playernum, struct savebuffer *buffer, s32 arg2);
 void mpplayerfileSaveWad(s32 playernum, struct savebuffer *buffer);
 void mpplayerfileGetOverview(char *arg0, char *name, u32 *playtime);
-s32 mpplayerfileSave(s32 playernum, s32 device, s32 arg2, u16 deviceserial);
+s32 mpplayerfileSave(s32 playernum, s32 device, s32 fileid, u16 deviceserial);
 s32 mpplayerfileLoad(s32 playernum, s32 device, s32 arg2, u16 deviceserial);
 s32 mpGetNumPresets(void);
 bool mpIsPresetUnlocked(s32 presetnum);
diff --git a/src/include/game/pak/pak.h b/src/include/game/pak/pak.h
index 286b43633..9cd87c354 100644
--- a/src/include/game/pak/pak.h
+++ b/src/include/game/pak/pak.h
@@ -12,8 +12,8 @@ u32 pakGenerateSerial(s8 device);
 bool pakIsMemoryPak(s8 device);
 s32 pakGetFileIdsByType(s8 device, u32 filetype, u32 *fileids);
 s32 pak0f1167d8(s8 device);
-s32 pak0f116800(s8 device, s32 fileid, u8 *body, s32 arg3);
-s32 pak0f116828(s8 device, s32 fileid, s32 filetype, u8 *body, s32 *outfileid, s32 arg5);
+s32 pakReadBodyAtGuid(s8 device, s32 fileid, u8 *body, s32 arg3);
+s32 pakSaveAtGuid(s8 device, s32 fileid, s32 filetype, u8 *body, s32 *outfileid, u8 *olddata);
 bool pakDeleteFile(s8 device, s32 fileid);
 s32 pakDeleteGameNote(s8 device, u16 company_code, u32 game_code, char *game_name, char *ext_name);
 s32 pak0f1168c4(s8 device, struct pakdata **arg1);
@@ -41,7 +41,7 @@ bool pakRetrieveBlockFromCache(s8 device, u32 offset, u8 *dst);
 u32 pakReadHeaderAtOffset(s8 device, u32 offset, struct pakfileheader *header);
 void pakDumpBuffer(u8 *buffer, u32 len, char *name);
 void pakDumpEeprom(void);
-s32 pak0f11789c(s8 device, s32 fileid, s32 filetype, u8 *body, s32 *outfileid, s32 arg5);
+s32 _pakSaveAtGuid(s8 device, s32 fileid, s32 filetype, u8 *newdata, s32 *outfileid, u8 *olddata);
 
 #if VERSION >= VERSION_NTSC_1_0
 s32 pakInitPak(OSMesgQueue *mq, OSPfs *pfs, s32 channel, s32 *arg3);
@@ -68,7 +68,7 @@ void pak0f1185e0(s8 device, s32 arg1, s32 arg2);
 u32 pak0f118674(s8 device, u32 filetype, u8 *olddata);
 void pakInitAll(void);
 void pakCalculateChecksum(u8 *arg0, u8 *arg1, u16 *arg2);
-s32 pak0f118bc8(s8 device, s32 fileid, u8 *body, s32 arg3);
+s32 _pakReadBodyAtGuid(s8 device, s32 fileid, u8 *body, s32 arg3);
 s32 _pakGetFileIdsByType(s8 device, u32 filetype, u32 *fileids);
 s32 pak0f1190bc(s8 device, s32 arg1, s32 *arg2);
 u32 pak0f119298(s8 device);
@@ -98,7 +98,7 @@ s32 pakScrub(s8 device);
 bool pak0f11b75c(s8 device, u32 *arg1);
 s32 pak0f11b86c(s32 device, u32 uVar2, u8 *data, struct pakfileheader *header, s32 arg3);
 bool pakReplaceFileAtOffsetWithBlank(s8 device, u32 offset);
-s32 pakWriteFile(s8 device, u32 offset, u32 filetype, u8 *newdata, s32 bodylen, s32 *outfileid, u8 *olddata, u32 fileid, u32 arg8);
+s32 pakWriteFileAtOffset(s8 device, u32 offset, u32 filetype, u8 *newdata, s32 bodylen, s32 *outfileid, u8 *olddata, u32 fileid, u32 generation);
 bool pakRepair(s8 device);
 bool pakHandleResult(s32 result, s8 device, u32 arg2, u32 arg3);
 void pak0f11c54c(void);
diff --git a/src/include/types.h b/src/include/types.h
index ee6f3a84d..4f06a2c04 100644
--- a/src/include/types.h
+++ b/src/include/types.h
@@ -6687,14 +6687,14 @@ struct pakthing {
 struct pakfileheader {
 	union {
 		struct {
-			u16 headersum[2];  // checksum from filetype to end of header
+			u16 headersum[2];       // checksum from filetype to end of header
 			u16 bodysum[2];
-			u32 filetype : 9; // PAKFILETYPE constant
-			u32 bodylen : 11; // not aligned
-			u32 filelen : 12; // aligned to 0x10
+			u32 filetype : 9;       // PAKFILETYPE constant
+			u32 bodylen : 11;       // not aligned
+			u32 filelen : 12;       // aligned to 0x10
 			u32 deviceserial : 13;
 			u32 fileid : 7;
-			u32 unk0c_21 : 9;
+			u32 generation : 9;     // increments by 1 each time the same file is saved
 			u32 occupied : 1;
 			u32 writecompleted : 1; // 0 while writing data, then updated to 1 afterwards
 			u32 version : 1;        // 0, but can be set to 1 using -forceversion argument