diff --git a/game/CMakeLists.txt b/game/CMakeLists.txt
index 4e2997a71..4aa8ff4cc 100644
--- a/game/CMakeLists.txt
+++ b/game/CMakeLists.txt
@@ -252,8 +252,13 @@ set(RUNTIME_SOURCE
         overlord/jak2/streamlist.cpp
         overlord/jak2/vag.cpp
         overlord/jak3/start.cpp
+        overlord/jak3/iso_fake.cpp
+        overlord/jak3/iso.cpp
         overlord/jak3/overlord.cpp
+        overlord/jak3/pagemanager.cpp
+        overlord/jak3/ramdisk.cpp
         overlord/jak3/sbank.cpp
+        overlord/jak3/srpc.cpp
         overlord/jak3/ssound.cpp
         overlord/jak3/vblank_handler.cpp
         runtime.cpp
diff --git a/game/overlord/jak3/basefile.h b/game/overlord/jak3/basefile.h
index da71cfaa4..1c0225b44 100644
--- a/game/overlord/jak3/basefile.h
+++ b/game/overlord/jak3/basefile.h
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "game/overlord/jak3/iso.h"
 #include "game/overlord/jak3/iso_structs.h"
 #include "game/overlord/jak3/overlord.h"
 
@@ -11,9 +12,8 @@ class CBaseFile {
   virtual EIsoStatus SyncRead() = 0;
   virtual void Close() = 0;
 
-    /* unk return values */
+  /* unk return values */
   virtual void Unk1() = 0;
   virtual void Unk2() = 0;
 };
 }  // namespace jak3
-
diff --git a/game/overlord/jak3/iso.cpp b/game/overlord/jak3/iso.cpp
index ab9790d1f..d5d69aebc 100644
--- a/game/overlord/jak3/iso.cpp
+++ b/game/overlord/jak3/iso.cpp
@@ -2,7 +2,11 @@
 
 #include <cstring>
 
+#include "common/log/log.h"
+
+#include "game/common/dgo_rpc_types.h"
 #include "game/overlord/jak3/basefilesystem.h"
+#include "game/overlord/jak3/iso_fake.h"
 
 namespace jak3 {
 using namespace iop;
@@ -12,6 +16,27 @@ static ISO_LoadDGO s_LoadDGO;
 int s_nSyncMbx;
 CBaseFileSystem* g_pFileSystem;
 MsgPacket s_MsgPacket_NotOnStackSync[2];
+RPC_Dgo_Cmd s_aISO_RPCBuf[1];
+
+static void* RPC_DGO(u32 fno, void* data, int size) {
+  lg::error("RPC_DGO UNIMPLEMENTED");
+  return nullptr;
+}
+
+static u32 DGOThread() {
+  sceSifQueueData dq;
+  sceSifServeData serve;
+
+  CpuDisableIntr();
+  sceSifInitRpc(0);
+  sceSifSetRpcQueue(&dq, GetThreadId());
+  sceSifRegisterRpc(&serve, 0xfab3, RPC_DGO, s_aISO_RPCBuf, sizeof(s_aISO_RPCBuf), nullptr, nullptr,
+                    &dq);
+  CpuEnableIntr();
+  sceSifRpcLoop(&dq);
+
+  return 0;
+}
 
 /* COMPLETE */
 void InitDriver() {
@@ -47,6 +72,7 @@ int InitISOFS(const char* fs_mode, const char* loading_sceeen) {
 
   memset(&s_LoadDGO, 0, sizeof(s_LoadDGO));
   s_nISOInitFlag = 1;
+  g_pFileSystem = &g_FakeISOCDFileSystem;
 
   return s_nISOInitFlag;
 }
diff --git a/game/overlord/jak3/iso.h b/game/overlord/jak3/iso.h
index 7ce81b4d0..4e03d677f 100644
--- a/game/overlord/jak3/iso.h
+++ b/game/overlord/jak3/iso.h
@@ -21,4 +21,5 @@ struct ISO_Msg : ISO_Hdr {};
 
 struct ISO_LoadDGO : ISO_Msg {};
 
+int InitISOFS(const char* fs_mode, const char* loading_sceeen);
 }  // namespace jak3
diff --git a/game/overlord/jak3/iso_fake.cpp b/game/overlord/jak3/iso_fake.cpp
new file mode 100644
index 000000000..23ba9a246
--- /dev/null
+++ b/game/overlord/jak3/iso_fake.cpp
@@ -0,0 +1,36 @@
+#include "iso_fake.h"
+
+namespace jak3 {
+CFakeISOCDFileSystem g_FakeISOCDFileSystem;
+
+int CFakeISOCDFileSystem::Init() {
+  return 0;
+}
+
+void CFakeISOCDFileSystem::PollDrive() {}
+
+const ISOFileDef* CFakeISOCDFileSystem::Find(const char* name) {
+  return nullptr;
+}
+
+const ISOFileDef* CFakeISOCDFileSystem::FindIN(const char* name) {
+  return nullptr;
+}
+
+int CFakeISOCDFileSystem::GetLength(const ISOFileDef* def) {
+  return 0;
+}
+
+int CFakeISOCDFileSystem::Open(const ISOFileDef* def, int offset, EFileComp mode) {
+  return 0;
+}
+
+int CFakeISOCDFileSystem::OpenWad(const ISOFileDef* def, int offset) {
+  return 0;
+}
+
+VagDirEntryJak3* CFakeISOCDFileSystem::FindVagFile(const char* name) {
+  return nullptr;
+}
+
+}  // namespace jak3
diff --git a/game/overlord/jak3/iso_fake.h b/game/overlord/jak3/iso_fake.h
new file mode 100644
index 000000000..b73d3aac9
--- /dev/null
+++ b/game/overlord/jak3/iso_fake.h
@@ -0,0 +1,35 @@
+#ifndef ISO_FAKE_H_
+#define ISO_FAKE_H_
+
+#include "basefile.h"
+#include "basefilesystem.h"
+
+#include "game/overlord/jak3/iso.h"
+
+namespace jak3 {
+class CFakeISOCDFileSystem : public CBaseFileSystem {
+  int Init() override;
+  void PollDrive() override;
+  const ISOFileDef* Find(const char* name) override;
+  const ISOFileDef* FindIN(const char* name) override;
+  int GetLength(const ISOFileDef* def) override;
+  int Open(const ISOFileDef* def, int offset, EFileComp mode) override;
+  int OpenWad(const ISOFileDef* def, int offset) override;
+  VagDirEntryJak3* FindVagFile(const char* name) override;
+};
+
+class CFakeISOCDFile : public CBaseFile {
+  EIsoStatus BeginRead(ISOBuffer*) override;
+  EIsoStatus SyncRead() override;
+  void Close() override;
+
+  /* unk return values */
+  void Unk1() override;
+  void Unk2() override;
+};
+
+extern CFakeISOCDFileSystem g_FakeISOCDFileSystem;
+
+}  // namespace jak3
+
+#endif  // ISO_FAKE_H_
diff --git a/game/overlord/jak3/iso_structs.h b/game/overlord/jak3/iso_structs.h
index 8e3b997c2..68cb5d2fd 100644
--- a/game/overlord/jak3/iso_structs.h
+++ b/game/overlord/jak3/iso_structs.h
@@ -24,7 +24,7 @@ struct VagDirJak3 {
   u32 version;
   u32 count;
   VagDirEntryJak3 entries[0];
-} dir;
+};
 
 struct VagDirEntry {};
 
diff --git a/game/overlord/jak3/ramdisk.cpp b/game/overlord/jak3/ramdisk.cpp
index 43a960253..09e285c72 100644
--- a/game/overlord/jak3/ramdisk.cpp
+++ b/game/overlord/jak3/ramdisk.cpp
@@ -23,7 +23,8 @@ u32 Thread_Server() {
   CpuDisableIntr();
   sceSifInitRpc(0);
   sceSifSetRpcQueue(&dq, GetThreadId());
-  sceSifRegisterRpc(&serve, 0xfab2, RPC_Ramdisk, gRamDisk_RPCBUF, nullptr, nullptr, &dq);
+  sceSifRegisterRpc(&serve, 0xfab2, RPC_Ramdisk, gRamDisk_RPCBUF, sizeof(gRamDisk_RPCBUF), nullptr,
+                    nullptr, &dq);
   CpuEnableIntr();
   sceSifRpcLoop(&dq);
 
diff --git a/game/overlord/jak3/srpc.cpp b/game/overlord/jak3/srpc.cpp
index caf82f752..f3b9a5470 100644
--- a/game/overlord/jak3/srpc.cpp
+++ b/game/overlord/jak3/srpc.cpp
@@ -30,7 +30,8 @@ u32 Thread_Player() {
   CpuDisableIntr();
   sceSifInitRpc(0);
   sceSifSetRpcQueue(&dq, GetThreadId());
-  sceSifRegisterRpc(&serve, 0xfab0, RPC_Player, s_anSRPC_PlayerBuf, nullptr, nullptr, &dq);
+  sceSifRegisterRpc(&serve, 0xfab0, RPC_Player, s_anSRPC_PlayerBuf, sizeof(s_anSRPC_PlayerBuf),
+                    nullptr, nullptr, &dq);
   CpuEnableIntr();
   sceSifRpcLoop(&dq);
 
@@ -44,7 +45,8 @@ u32 Thread_Loader() {
   CpuDisableIntr();
   sceSifInitRpc(0);
   sceSifSetRpcQueue(&dq, GetThreadId());
-  sceSifRegisterRpc(&serve, 0xfab1, RPC_Loader, s_anSRPC_LoaderBuf, nullptr, nullptr, &dq);
+  sceSifRegisterRpc(&serve, 0xfab1, RPC_Loader, s_anSRPC_LoaderBuf, sizeof(s_anSRPC_LoaderBuf),
+                    nullptr, nullptr, &dq);
   CpuEnableIntr();
   sceSifRpcLoop(&dq);
 
diff --git a/game/overlord/jak3/start.cpp b/game/overlord/jak3/start.cpp
index 4b1695b6d..4b08ce29a 100644
--- a/game/overlord/jak3/start.cpp
+++ b/game/overlord/jak3/start.cpp
@@ -1,6 +1,7 @@
 #include <cstdio>
 #include <cstring>
 
+#include "iso.h"
 #include "overlord.h"
 #include "ramdisk.h"
 #include "sbank.h"
@@ -70,7 +71,7 @@ int start_overlord(int argc, const char* const* argp) {
     return 1;
   }
 
-  //CDvdDriver::Initialize(&g_DvdDriver);
+  // CDvdDriver::Initialize(&g_DvdDriver);
   InitISOFS(argp[1], argp[2]);
 
   StartThread(g_nServerThreadID, 0);
diff --git a/game/runtime.cpp b/game/runtime.cpp
index b39317b60..b1a2347cd 100644
--- a/game/runtime.cpp
+++ b/game/runtime.cpp
@@ -4,6 +4,7 @@
  */
 
 #include "common/common_types.h"
+
 #ifdef OS_POSIX
 #include <unistd.h>
 
@@ -78,6 +79,7 @@
 #include "game/overlord/jak2/stream.h"
 #include "game/overlord/jak2/streamlist.h"
 #include "game/overlord/jak2/vag.h"
+#include "game/overlord/jak3/overlord.h"
 #include "game/system/Deci2Server.h"
 #include "game/system/iop_thread.h"
 #include "sce/deci2.h"
@@ -323,9 +325,11 @@ void iop_runner(SystemThreadInterface& iface, GameVersion version) {
         jak1::start_overlord_wrapper(iop.overlord_argc, iop.overlord_argv, &complete);
         break;
       case GameVersion::Jak2:
-      case GameVersion::Jak3:  // TODO: jak3 using jak2's overlord.
         jak2::start_overlord_wrapper(iop.overlord_argc, iop.overlord_argv, &complete);
         break;
+      case GameVersion::Jak3:
+        jak3::start_overlord_wrapper(iop.overlord_argc, iop.overlord_argv, &complete);
+        break;
       default:
         ASSERT_NOT_REACHED();
     }