diff --git a/include/MetroidPrime/Player/CGameState.hpp b/include/MetroidPrime/Player/CGameState.hpp
index e75defc6..16d11b58 100644
--- a/include/MetroidPrime/Player/CGameState.hpp
+++ b/include/MetroidPrime/Player/CGameState.hpp
@@ -22,6 +22,7 @@ public:
 
   rstl::rc_ptr< CPlayerState >& PlayerState();
   CAssetId CurrentWorldAssetId();
+  void WriteBackupBuf();
 
   CSystemOptions& SystemOptions() { return xa8_systemOptions; }
   CGameOptions& GameOptions() { return x17c_gameOptions; }
@@ -29,6 +30,8 @@ public:
   uint& SaveIdx() { return x20c_saveIdx; }
   u64& CardSerial() { return x210_cardSerial; }
   rstl::vector< uchar >& BackupBuf() { return x218_backupBuf; }
+  void SetCardSerial(u64 serial) { x210_cardSerial = serial; }
+  u64 GetCardSerial() const { return x210_cardSerial; }
 
   struct GameFileStateInfo {
     double x0_playTime;
diff --git a/src/MetroidPrime/CMemoryCardDriver.cpp b/src/MetroidPrime/CMemoryCardDriver.cpp
index 799344ec..cb89bd1c 100644
--- a/src/MetroidPrime/CMemoryCardDriver.cpp
+++ b/src/MetroidPrime/CMemoryCardDriver.cpp
@@ -338,7 +338,10 @@ void CMemoryCardDriver::StartFileRenameBtoA() {
   }
 }
 
-void CMemoryCardDriver::WriteBackupBuf() {}
+void CMemoryCardDriver::WriteBackupBuf() {
+  gpGameState->WriteBackupBuf();
+  gpGameState->SetCardSerial(x28_cardSerial);
+}
 
 void CMemoryCardDriver::UpdateFileAltDeleteTransactional(ECardResult) {}