diff --git a/src/lib/ultra/os/initialize.c b/src/lib/ultra/os/initialize.c
index 054a2c096..01d9a6330 100644
--- a/src/lib/ultra/os/initialize.c
+++ b/src/lib/ultra/os/initialize.c
@@ -50,7 +50,7 @@ void osInitialize(void)
 
 	osWritebackDCache((void *)UT_VEC, E_VEC - UT_VEC + sizeof(__osExceptionVector));
 	osInvalICache((void *)UT_VEC, E_VEC - UT_VEC + sizeof(__osExceptionVector));
-	func00005dc0();
+	osCartRomInit();
 	osMapTLBRdb();
 
 #if !PAL
@@ -90,35 +90,25 @@ void osInitialize(void)
 	*(u32 *)PHYS_TO_K1(AI_BITRATE_REG) = 0xf;
 }
 
-GLOBAL_ASM(
-glabel func00005dc0
-/*     5dc0:	3c028009 */ 	lui	$v0,%hi(CartRomHandle)
-/*     5dc4:	244202a0 */ 	addiu	$v0,$v0,%lo(CartRomHandle)
-/*     5dc8:	24030007 */ 	addiu	$v1,$zero,0x7
-/*     5dcc:	a0430004 */ 	sb	$v1,0x4($v0)
-/*     5dd0:	3c0ea460 */ 	lui	$t6,0xa460
-/*     5dd4:	8dcf0014 */ 	lw	$t7,0x14($t6)
-/*     5dd8:	3c18a460 */ 	lui	$t8,0xa460
-/*     5ddc:	3c08a460 */ 	lui	$t0,0xa460
-/*     5de0:	a04f0005 */ 	sb	$t7,0x5($v0)
-/*     5de4:	8f190018 */ 	lw	$t9,0x18($t8)
-/*     5de8:	3c0aa460 */ 	lui	$t2,0xa460
-/*     5dec:	3c048009 */ 	lui	$a0,%hi(LeoDiskHandle)
-/*     5df0:	a0590008 */ 	sb	$t9,0x8($v0)
-/*     5df4:	8d09001c */ 	lw	$t1,0x1c($t0)
-/*     5df8:	24840318 */ 	addiu	$a0,$a0,%lo(LeoDiskHandle)
-/*     5dfc:	3c0ca460 */ 	lui	$t4,0xa460
-/*     5e00:	a0490006 */ 	sb	$t1,0x6($v0)
-/*     5e04:	8d4b0020 */ 	lw	$t3,0x20($t2)
-/*     5e08:	a0830004 */ 	sb	$v1,0x4($a0)
-/*     5e0c:	a04b0007 */ 	sb	$t3,0x7($v0)
-/*     5e10:	8d8d0024 */ 	lw	$t5,0x24($t4)
-/*     5e14:	a08d0005 */ 	sb	$t5,0x5($a0)
-/*     5e18:	8dcf0028 */ 	lw	$t7,0x28($t6)
-/*     5e1c:	a08f0008 */ 	sb	$t7,0x8($a0)
-/*     5e20:	8f19002c */ 	lw	$t9,0x2c($t8)
-/*     5e24:	a0990006 */ 	sb	$t9,0x6($a0)
-/*     5e28:	8d090030 */ 	lw	$t1,0x30($t0)
-/*     5e2c:	03e00008 */ 	jr	$ra
-/*     5e30:	a0890007 */ 	sb	$t1,0x7($a0)
-);
+extern OSPiHandle CartRomHandle;
+extern OSPiHandle LeoDiskHandle;
+
+/**
+ * According to Nintendo's SDK this function should return a pointer to an
+ * OSPiHandle, but the function only matches if the return statement is omitted.
+ * By chance the value in v0 happens to be &CartRomHandle anyway.
+ */
+OSPiHandle *osCartRomInit(void)
+{
+	CartRomHandle.type = DEVICE_TYPE_INIT;
+	CartRomHandle.latency = IO_READ(0xa4600014);
+	CartRomHandle.pulse = IO_READ(0xa4600018);
+	CartRomHandle.pageSize = IO_READ(0xa460001c);
+	CartRomHandle.relDuration = IO_READ(0xa4600020);
+
+	LeoDiskHandle.type = DEVICE_TYPE_INIT;
+	LeoDiskHandle.latency = IO_READ(0xa4600024);
+	LeoDiskHandle.pulse = IO_READ(0xa4600028);
+	LeoDiskHandle.pageSize = IO_READ(0xa460002c);
+	LeoDiskHandle.relDuration = IO_READ(0xa4600030);
+}