diff --git a/Source/Project64/N64 System/N64 Rom Class.cpp b/Source/Project64/N64 System/N64 Rom Class.cpp
index a116a277f..0bf2230a4 100644
--- a/Source/Project64/N64 System/N64 Rom Class.cpp	
+++ b/Source/Project64/N64 System/N64 Rom Class.cpp	
@@ -256,6 +256,78 @@ void CN64Rom::CalculateCicChip()
 
 }
 
+void CN64Rom::CalculateRomCrc()
+{
+	DWORD t0, t1, t2, t3, t4, t5, t7;
+	DWORD a0, a1, a2, a3;
+	DWORD s0;
+	DWORD v0, v1;
+
+	DWORD OldProtect;
+	VirtualProtect(m_ROMImage, m_RomFileSize, PAGE_READWRITE, &OldProtect);
+
+	switch (m_CicChip) {
+	case CIC_NUS_6101:
+	case CIC_NUS_6102:
+	{
+		v1 = 0;
+		t0 = 0;
+
+		t5 = 0x20;
+
+		v0 = 0xF8CA4DDB + 1; // 0xFFFFFFFF & (0x3F * 0x5D588B65)
+		a3 = v0;
+		t2 = v0;
+		t3 = v0;
+		s0 = v0;
+		a2 = v0;
+		t4 = v0;
+
+		for (t0 = 0, t1 = 0x1000; t0 < 0x00100000; t0 += 4, t1 += 4){
+			v0 = *(DWORD *)(m_ROMImage + t1);
+
+			v1 = a3 + v0;
+			a1 = v1;
+
+			if (v1 < a3) t2 += 0x1;
+			v1 = v0 & 0x001F;
+			t7 = t5 - v1;
+
+			a0 = (v0 << v1) | (v0 >> t7);
+
+			a3 = a1;
+			t3 = t3 ^ v0;
+
+			s0 = s0 + a0;
+			if (a2 < v0){
+				a2 = a3 ^ v0 ^ a2;
+			}
+			else{
+				a2 = a2 ^ a0;
+			}
+
+			t4 = (v0 ^ s0) + t4;
+		}
+		a3 = a3 ^ t2 ^ t3;
+		s0 = s0 ^ a2 ^ t4;
+
+		*(DWORD *)(m_ROMImage + 0x10) = a3;
+		*(DWORD *)(m_ROMImage + 0x14) = s0;
+		break;
+	}
+	case CIC_NUS_6103:
+	case CIC_NUS_6105:
+	case CIC_NUS_6106:
+	case CIC_NUS_8303:
+	case CIC_NUS_DDIPL:
+	case CIC_UNKNOWN:
+	default:
+		break;
+	}
+
+	VirtualProtect(m_ROMImage, m_RomFileSize, PAGE_READONLY, &OldProtect);
+}
+
 CICChip CN64Rom::CicChipID()
 {
 	return m_CicChip;
@@ -471,6 +543,13 @@ bool CN64Rom::LoadN64Image ( const char * FileLoc, bool LoadBootCodeOnly ) {
 	{
 		SaveRomSettingID(false);
 	}
+	
+	if (g_Settings->LoadBool(Game_CRC_Recalc))
+	{
+		//Calculate ROM Header CRC
+		CalculateRomCrc();
+	}
+	
 	return true;
 }
 
diff --git a/Source/Project64/N64 System/N64 Rom Class.h b/Source/Project64/N64 System/N64 Rom Class.h
index a076e2b5f..363add814 100644
--- a/Source/Project64/N64 System/N64 Rom Class.h	
+++ b/Source/Project64/N64 System/N64 Rom Class.h	
@@ -33,6 +33,7 @@ class CN64Rom :
 	void   SetError                ( LanguageStringID ErrorMsg );
 	static void  __stdcall NotificationCB ( LPCWSTR Status, CN64Rom * _this );
 	void   CalculateCicChip        ();
+	void   CalculateRomCrc         ();
 
 public:
 	CN64Rom();
diff --git a/Source/Project64/Settings.h b/Source/Project64/Settings.h
index ad66e0a14..94b407a72 100644
--- a/Source/Project64/Settings.h
+++ b/Source/Project64/Settings.h
@@ -97,6 +97,7 @@ enum SettingID {
 	Rdb_AiCountPerBytes,
 	Rdb_AudioResetOnLoad,
 	Rdb_AllowROMWrites,
+	Rdb_CRC_Recalc,
 
 	//Individual Game Settings
 	Game_IniKey,
@@ -143,6 +144,7 @@ enum SettingID {
 	Game_AiCountPerBytes,
 	Game_AudioResetOnLoad,
 	Game_AllowROMWrites,
+	Game_CRC_Recalc,
 
 	// General Game running info
 	GameRunning_LoadingInProgress,
diff --git a/Source/Project64/Settings/Settings Class.cpp b/Source/Project64/Settings/Settings Class.cpp
index 513a7a3f9..67609581a 100644
--- a/Source/Project64/Settings/Settings Class.cpp	
+++ b/Source/Project64/Settings/Settings Class.cpp	
@@ -169,6 +169,7 @@ void CSettings::AddHowToHandleSetting ()
 	AddHandler(Rdb_AiCountPerBytes,     new CSettingTypeRomDatabase("AiCountPerBytes",400));
 	AddHandler(Rdb_AudioResetOnLoad,    new CSettingTypeRDBYesNo("AudioResetOnLoad", false));
 	AddHandler(Rdb_AllowROMWrites,      new CSettingTypeRDBYesNo("AllowROMWrites", false));
+	AddHandler(Rdb_CRC_Recalc,          new CSettingTypeRDBYesNo("CRC-Recalc", false));
 	
 	AddHandler(Game_IniKey,             new CSettingTypeTempString(""));
 	AddHandler(Game_GameName,           new CSettingTypeTempString(""));
@@ -214,6 +215,7 @@ void CSettings::AddHowToHandleSetting ()
 	AddHandler(Game_AiCountPerBytes,    new CSettingTypeGame("AiCountPerBytes",Rdb_AiCountPerBytes));
 	AddHandler(Game_AudioResetOnLoad,   new CSettingTypeGame("AudioResetOnLoad", Rdb_AudioResetOnLoad));
 	AddHandler(Game_AllowROMWrites,     new CSettingTypeGame("AllowROMWrites", Rdb_AllowROMWrites));
+	AddHandler(Game_CRC_Recalc,         new CSettingTypeGame("CRC-Recalc", Rdb_CRC_Recalc));
 
 	//User Interface
 	AddHandler(UserInterface_BasicMode,        new CSettingTypeApplication("","Basic Mode",          (DWORD)true));