diff --git a/asm/MetroidPrime/CMemoryCardDriver.s b/asm/MetroidPrime/CMemoryCardDriver.s
index 72386115..79c8e80a 100644
--- a/asm/MetroidPrime/CMemoryCardDriver.s
+++ b/asm/MetroidPrime/CMemoryCardDriver.s
@@ -664,7 +664,7 @@ lbl_8024CA74:
 /* 8024CA88 002499E8  48 0F 28 B5 */	bl __ct__16CMemoryStreamOutFPvUlQ216CMemoryStreamOut10EOwnerShipi
 /* 8024CA8C 002499EC  80 6D A0 80 */	lwz r3, gpGameState@sda21(r13)
 /* 8024CA90 002499F0  38 81 00 10 */	addi r4, r1, 0x10
-/* 8024CA94 002499F4  4B F8 75 89 */	bl sub_801d401c
+/* 8024CA94 002499F4  4B F8 75 89 */	bl WriteSystemOptions__10CGameStateFR13COutputStream
 /* 8024CA98 002499F8  38 61 00 10 */	addi r3, r1, 0x10
 /* 8024CA9C 002499FC  38 80 FF FF */	li r4, -1
 /* 8024CAA0 00249A00  48 0F 28 21 */	bl __dt__16CMemoryStreamOutFv
diff --git a/asm/MetroidPrime/Player/CGameState.s b/asm/MetroidPrime/Player/CGameState.s
index abb7eeb7..db90b11a 100644
--- a/asm/MetroidPrime/Player/CGameState.s
+++ b/asm/MetroidPrime/Player/CGameState.s
@@ -646,8 +646,8 @@ lbl_801D3FC0:
 /* 801D4014 001D0F74  38 21 00 10 */	addi r1, r1, 0x10
 /* 801D4018 001D0F78  4E 80 00 20 */	blr
 
-.global sub_801d401c
-sub_801d401c:
+.global WriteSystemOptions__10CGameStateFR13COutputStream
+WriteSystemOptions__10CGameStateFR13COutputStream:
 /* 801D401C 001D0F7C  94 21 FF F0 */	stwu r1, -0x10(r1)
 /* 801D4020 001D0F80  7C 08 02 A6 */	mflr r0
 /* 801D4024 001D0F84  38 63 00 A8 */	addi r3, r3, 0xa8
diff --git a/include/Kyoto/Streams/CMemoryStreamOut.hpp b/include/Kyoto/Streams/CMemoryStreamOut.hpp
index 4befd536..e2c58877 100644
--- a/include/Kyoto/Streams/CMemoryStreamOut.hpp
+++ b/include/Kyoto/Streams/CMemoryStreamOut.hpp
@@ -10,7 +10,7 @@ public:
     kOS_NotOwned,
   };
 
-  CMemoryStreamOut(uchar* buffer, size_t len, EOwnerShip ownerShip = kOS_NotOwned, int blockLen = 4096);
+  CMemoryStreamOut(void* buffer, size_t len, EOwnerShip ownerShip = kOS_NotOwned, int blockLen = 4096);
   virtual ~CMemoryStreamOut();
 };
 
diff --git a/include/MetroidPrime/Player/CGameState.hpp b/include/MetroidPrime/Player/CGameState.hpp
index 9276fc77..34e2669b 100644
--- a/include/MetroidPrime/Player/CGameState.hpp
+++ b/include/MetroidPrime/Player/CGameState.hpp
@@ -15,12 +15,15 @@
 #include "rstl/reserved_vector.hpp"
 #include "rstl/vector.hpp"
 
+class CMemoryStreamOut;
 class CGameState {
 public:
   CGameState();
   CGameState(CInputStream& in, int saveIdx);
 
   void ReadSystemOptions(CInputStream& in);
+  void PutTo(CMemoryStreamOut& out);
+  void WriteSystemOptions(COutputStream& out);
 
   rstl::rc_ptr< CPlayerState >& PlayerState();
   CAssetId CurrentWorldAssetId();
diff --git a/src/MetroidPrime/CMemoryCardDriver.cpp b/src/MetroidPrime/CMemoryCardDriver.cpp
index 70f60638..4a4c4f71 100644
--- a/src/MetroidPrime/CMemoryCardDriver.cpp
+++ b/src/MetroidPrime/CMemoryCardDriver.cpp
@@ -728,7 +728,18 @@ void CMemoryCardDriver::BuildNewFileSlot(int saveIdx) {
   gpGameState->SystemOptions().SetHasFusion(fusionBackup);
 }
 
-void CMemoryCardDriver::BuildExistingFileSlot(int) {}
+void CMemoryCardDriver::BuildExistingFileSlot(int saveIdx) {
+  gpGameState->SetFileIdx(saveIdx);
+
+  rstl::auto_ptr< SGameFileSlot >& slot = xe4_fileSlots[saveIdx];
+  if (slot.null())
+    slot = new SGameFileSlot();
+  else
+    slot->InitializeFromGameState();
+
+  CMemoryStreamOut w(x30_systemData.data(), x30_systemData.capacity());
+  gpGameState->WriteSystemOptions(w);
+}
 
 void CMemoryCardDriver::ImportPersistentOptions() {}