diff --git a/src/game/game_1531a0.c b/src/game/game_1531a0.c
index d2ba12bc1..864362251 100644
--- a/src/game/game_1531a0.c
+++ b/src/game/game_1531a0.c
@@ -771,25 +771,11 @@ void func0f153e4c(void)
 	var800a45d0.unk00 = 0;
 }
 
-GLOBAL_ASM(
-glabel func0f153e58
-/*  f153e58:	3c04800a */ 	lui	$a0,%hi(var800a45d0)
-/*  f153e5c:	248445d0 */ 	addiu	$a0,$a0,%lo(var800a45d0)
-/*  f153e60:	90820000 */ 	lbu	$v0,0x0($a0)
-/*  f153e64:	304e0001 */ 	andi	$t6,$v0,0x1
-/*  f153e68:	000e102b */ 	sltu	$v0,$zero,$t6
-/*  f153e6c:	10400007 */ 	beqz	$v0,.L0f153e8c
-/*  f153e70:	00000000 */ 	nop
-/*  f153e74:	90830018 */ 	lbu	$v1,0x18($a0)
-/*  f153e78:	2c620001 */ 	sltiu	$v0,$v1,0x1
-/*  f153e7c:	14400003 */ 	bnez	$v0,.L0f153e8c
-/*  f153e80:	00000000 */ 	nop
-/*  f153e84:	38620002 */ 	xori	$v0,$v1,0x2
-/*  f153e88:	2c420001 */ 	sltiu	$v0,$v0,0x1
-.L0f153e8c:
-/*  f153e8c:	03e00008 */ 	jr	$ra
-/*  f153e90:	00000000 */ 	nop
-);
+s32 func0f153e58(void)
+{
+	return (var800a45d0.unk00 & 1)
+		&& (var800a45d0.unk18 == 0 || var800a45d0.unk18 == 2);
+}
 
 GLOBAL_ASM(
 glabel func0f153e94
diff --git a/src/include/game/game_1531a0.h b/src/include/game/game_1531a0.h
index 5d73fe871..2d378ebf0 100644
--- a/src/include/game/game_1531a0.h
+++ b/src/include/game/game_1531a0.h
@@ -29,7 +29,7 @@ u32 func0f153d50(void);
 u32 func0f153d88(void);
 void func0f153e38(u32 colour1, u32 colour2);
 void func0f153e4c(void);
-u32 func0f153e58(void);
+s32 func0f153e58(void);
 u32 func0f153e94(void);
 u32 func0f1543ac(void);
 u32 func0f154ecc(void);
diff --git a/src/include/types.h b/src/include/types.h
index 76e65f86e..714b173a8 100644
--- a/src/include/types.h
+++ b/src/include/types.h
@@ -6841,7 +6841,7 @@ struct var800a45d0 {
 	/*0x0c*/ u32 unk0c;
 	/*0x10*/ u32 unk10;
 	/*0x14*/ u32 unk14;
-	/*0x18*/ u32 unk18;
+	/*0x18*/ u8 unk18;
 	/*0x1c*/ u32 unk1c;
 	/*0x20*/ u32 unk20;
 	/*0x24*/ u32 unk24;