diff --git a/source/gamecart/command_ntr.c b/source/gamecart/command_ntr.c
index 2c27b1f..f0f66f0 100644
--- a/source/gamecart/command_ntr.c
+++ b/source/gamecart/command_ntr.c
@@ -14,7 +14,7 @@ void NTR_CmdReset(void)
 
 int NTR_CmdGetCartId(void)
 {
-    int id;
+    u32 id;
     static const u32 getid_cmd[2] = { 0x90000000, 0x00000000 };
     NTR_SendCommand(getid_cmd, 0x4, NTRCARD_CLK_SLOW | NTRCARD_DELAY1(0x1FFF) | NTRCARD_DELAY2(0x18), &id);
     return id;
diff --git a/source/gamecart/protocol.c b/source/gamecart/protocol.c
index eb17c35..f750bc8 100644
--- a/source/gamecart/protocol.c
+++ b/source/gamecart/protocol.c
@@ -18,7 +18,7 @@
 
 extern u8* bottomScreen;
 
-int CartID = -1;
+u32 CartID = -1;
 u32 CartType = 0;
 
 static int A0_Response = -1;