diff --git a/config/eur/arm9/delinks.txt b/config/eur/arm9/delinks.txt
index 97a31c17..7e3f8e58 100644
--- a/config/eur/arm9/delinks.txt
+++ b/config/eur/arm9/delinks.txt
@@ -10,6 +10,9 @@ src/Main/Actor/ActorType.cpp:
     .text       start:0x0203e784 end:0x0203e8a0
     .bss        start:0x02069180 end:0x02069188
 
+src/Main/System/OverlayManager.cpp:
+    .text       start:0x0202ff44 end:0x0203003c
+
 libs/cpp/src/__register_global_object.cpp:
     complete
     .text       start:0x0204f8d4 end:0x0204f8f4
diff --git a/config/usa/arm9/delinks.txt b/config/usa/arm9/delinks.txt
index 5c30acbc..14d31538 100644
--- a/config/usa/arm9/delinks.txt
+++ b/config/usa/arm9/delinks.txt
@@ -10,6 +10,9 @@ src/Main/Actor/ActorType.cpp:
     .text       start:0x0203e740 end:0x0203e85c
     .bss        start:0x02069120 end:0x02069128
 
+src/Main/System/OverlayManager.cpp:
+    .text       start:0x0202ff40 end:0x02030038
+
 libs/cpp/src/__register_global_object.cpp:
     complete
     .text       start:0x0204f890 end:0x0204f8b0
diff --git a/docs/decompiling.md b/docs/decompiling.md
index 3ec8f682..e9f9c3b1 100644
--- a/docs/decompiling.md
+++ b/docs/decompiling.md
@@ -8,7 +8,7 @@ stuck or need assistance.
 - [The Ghidra project](#the-ghidra-project)
 
 ## Pick a source file
-See the `decomp` tag in the [issue tracker](https://github.com/AetiasHax/ph/issues?q=is%3Aopen+is%3Aissue+label%3Adecomp) for
+See the `decomp` tag in the [issue tracker](https://github.com/zeldaret/ph/issues?q=is%3Aopen+is%3Aissue+label%3Adecomp) for
 a list of delinked source files that are ready to be decompiled. This list grows as more source files are delinked from the
 rest of the base ROM.
 
diff --git a/include/System/OverlayManager.hpp b/include/System/OverlayManager.hpp
index 636208fc..4c83bbe4 100644
--- a/include/System/OverlayManager.hpp
+++ b/include/System/OverlayManager.hpp
@@ -6,6 +6,7 @@
 
 typedef u32 OverlayId;
 enum OverlayId_ {
+    OverlayId_None = -1,
     OverlayId_Core,
     OverlayId_01,
     OverlayId_02,
diff --git a/libs/nds/include/nds/Overlay.h b/libs/nds/include/nds/Overlay.h
index 7a8c6fa9..5339a9d7 100644
--- a/libs/nds/include/nds/Overlay.h
+++ b/libs/nds/include/nds/Overlay.h
@@ -1,6 +1,10 @@
 #ifndef _NDS_OVERLAY_H
 #define _NDS_OVERLAY_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef struct Overlay {
     /* 00 */ unk32 mId;
     /* 04 */ void *mBaseAddress;
@@ -27,4 +31,8 @@ bool Overlay_Destroy(Overlay *overlay);
 bool Overlay_Load(Overlay *overlay, unk32 param2);
 bool Overlay_Unload(Overlay *overlay, unk32 param2);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/Main/System/OverlayManager.cpp b/src/Main/System/OverlayManager.cpp
index 9c50ebb6..8fff1fc6 100644
--- a/src/Main/System/OverlayManager.cpp
+++ b/src/Main/System/OverlayManager.cpp
@@ -1,7 +1,88 @@
 #include "System/OverlayManager.hpp"
+#include "global.h"
+#include "nds/Overlay.h"
 
-void OverlayManager::Load(OverlayIndex index, OverlayId id) {}
-void OverlayManager::LoadIfNotLoaded(OverlayIndex index, OverlayId id) {}
-void OverlayManager::Unload(OverlayIndex index) {}
-void OverlayManager::LoadOverlaySetup(s32 index) {}
-void OverlayManager::UnloadOverlaySetup() {}
+struct UnkStruct_020ee698 {
+    /* 00 */ unk8 mUnk_00[0x2C];
+    /* 2c */ unk32 mUnk_2c;
+    /* 30 */
+};
+extern UnkStruct_020ee698 data_ov000_020ee698;
+
+struct OverlaySetup {
+    /* 00 */ unk8 mUnk_00;
+    /* 01 */ unk8 mUnk_01;
+    /* 02 */ unk8 mUnk_02;
+    /* 03 */ unk8 mUnk_03;
+    /* 04 */ OverlayId slot1Overlay;
+    /* 08 */ OverlayId slot2Overlay;
+    /* 0c */ OverlayId slot3Overlay;
+    /* 10 */ OverlayId slot12Overlay;
+    /* 14 */ void *mUnk_14;
+    /* 18 */ void *mUnk_18;
+    /* 1c */
+};
+extern OverlaySetup gOverlaySetups[];
+
+extern u32 *data_027e0ce0[];
+extern "C" void func_ov007_02102850(u32 **);
+extern "C" void func_ov007_021028a0(u32 **);
+
+THUMB void OverlayManager::Load(OverlayIndex index, OverlayId id) {
+    if (id != OverlayId_None) {
+        Overlay_Load(NULL, id);
+    }
+
+    this->mLoadedOverlays[index] = id;
+}
+
+THUMB void OverlayManager::LoadIfNotLoaded(OverlayIndex index, OverlayId id) {
+    OverlayId loadedId = this->mLoadedOverlays[index];
+
+    if (loadedId != id) {
+        this->Unload(index);
+        this->Load(index, id);
+    }
+}
+
+THUMB void OverlayManager::Unload(OverlayIndex index) {
+    if (this->mLoadedOverlays[index] != OverlayId_None) {
+        Overlay_Unload(NULL, this->mLoadedOverlays[index]);
+        this->mLoadedOverlays[index] = OverlayId_None;
+    }
+}
+
+//! TODO: solve the .word issue with the overlay IDs
+//! both functions should match otherwise
+THUMB void OverlayManager::LoadOverlaySetup(s32 index) {
+    OverlayId overlayId;
+    OverlaySetup *pSetup;
+
+    pSetup = &gOverlaySetups[index];
+
+    this->LoadIfNotLoaded(OverlayIndex_1, pSetup->slot1Overlay);
+    this->LoadIfNotLoaded(OverlayIndex_2, pSetup->slot2Overlay);
+
+    if (index == 5) {
+        func_ov007_02102850(data_027e0ce0);
+    } else {
+        overlayId = pSetup->slot12Overlay;
+
+        if (index == 6 && data_ov000_020ee698.mUnk_2c == 2) {
+            overlayId = OverlayId_61;
+        }
+
+        this->Load(OverlayIndex_3, pSetup->slot3Overlay);
+        this->Load(OverlayIndex_12, overlayId);
+    }
+}
+
+THUMB void OverlayManager::UnloadOverlaySetup() {
+    this->Unload(OverlayIndex_12);
+    this->Unload(OverlayIndex_3);
+
+    if (this->mLoadedOverlays[2] == OverlayId_07) {
+        func_ov007_021028a0(data_027e0ce0);
+        this->Unload(OverlayIndex_2);
+    }
+}
diff --git a/tools/configure.py b/tools/configure.py
old mode 100644
new mode 100755
index f3c34311..45d9824a
--- a/tools/configure.py
+++ b/tools/configure.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python3
+#!/usr/bin/env python3
 
 import os
 from pathlib import Path
diff --git a/tools/m2ctx.py b/tools/m2ctx.py
index f2275e33..7c20c34a 100755
--- a/tools/m2ctx.py
+++ b/tools/m2ctx.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 import sys
 import pyperclip
diff --git a/tools/ninja_syntax.py b/tools/ninja_syntax.py
index 2aa8456e..e0716e8a 100644
--- a/tools/ninja_syntax.py
+++ b/tools/ninja_syntax.py
@@ -1,5 +1,3 @@
-#!/usr/bin/python
-
 # Copyright 2011 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
diff --git a/tools/setup.py b/tools/setup.py
old mode 100644
new mode 100755
index f81ca25d..6e83c64a
--- a/tools/setup.py
+++ b/tools/setup.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 import requests
 import zipfile
 import io
diff --git a/tools/sha1.py b/tools/sha1.py
old mode 100644
new mode 100755
index 8cd6edd8..fd1cbda8
--- a/tools/sha1.py
+++ b/tools/sha1.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 from pathlib import Path
 import argparse