diff --git a/asm/entry.s b/asm/entry.s
index 1931e91d24..a8b7c1fdce 100644
--- a/asm/entry.s
+++ b/asm/entry.s
@@ -7,21 +7,23 @@
 
 .section .text
 
+.set BOOT_STACK_SIZE, 0x400
+
 glabel entrypoint # 0x80000400
-    lui   $t0, %hi(_bootSegmentBssStart) # $t0, 0x8001
-    addiu $t0, %lo(_bootSegmentBssStart) # addiu $t0, $t0, 0x2370
-    li    $t1, %lo(_bootSegmentBssSize) # li $t1, 0x4A30
+    lui   $t0, %hi(_bootSegmentBssStart)
+    addiu $t0, %lo(_bootSegmentBssStart)
+    li    $t1, %lo(_bootSegmentBssSize)
 .L8000040C:
     addi  $t1, $t1, -8
     sw    $zero, ($t0)
     sw    $zero, 4($t0)
     bnez  $t1, .L8000040C
      addi  $t0, $t0, 8
-    lui   $t2, %hi(bootproc) # $t2, 0x8000
-    lui   $sp, %hi(gMainThread) # $sp, 0x8001
-    addiu $t2, %lo(bootproc) # addiu $t2, $t2, 0x0498
+    lui   $t2, %hi(bootproc)
+    lui   $sp, %hi(sBootThreadStack + BOOT_STACK_SIZE)
+    addiu $t2, %lo(bootproc)
     jr    $t2
-     addiu $sp, %lo(gMainThread) # addiu $sp, $sp, 0x2D60
+     addiu $sp, %lo(sBootThreadStack + BOOT_STACK_SIZE)
     nop
     nop
     nop
diff --git a/asm/osInvalDCache.s b/asm/osInvalDCache.s
index 06ce7df15c..5f2e55866a 100644
--- a/asm/osInvalDCache.s
+++ b/asm/osInvalDCache.s
@@ -49,13 +49,13 @@ glabel osInvalDCache
 /* 006E84 80006284 00000000 */   nop   
 
 .L80006288:
-/* 006E88 80006288 3C088000 */  lui   $t0, %hi(D_80000010) # $t0, 0x8000
+/* 006E88 80006288 3C088000 */  lui   $t0, 0x8000
 /* 006E8C 8000628C 010B4821 */  addu  $t1, $t0, $t3
 /* 006E90 80006290 2529FFF0 */  addiu $t1, $t1, -0x10
 .L80006294:
 /* 006E94 80006294 BD010000 */  cache 1, ($t0)
 /* 006E98 80006298 0109082B */  sltu  $at, $t0, $t1
 /* 006E9C 8000629C 1420FFFD */  bnez  $at, .L80006294
-/* 006EA0 800062A0 25080010 */   addiu $t0, %lo(D_80000010) # addiu $t0, $t0, 0x10
+/* 006EA0 800062A0 25080010 */   addiu $t0, 0x10
 /* 006EA4 800062A4 03E00008 */  jr    $ra
 /* 006EA8 800062A8 00000000 */   nop   
diff --git a/asm/osInvalICache.s b/asm/osInvalICache.s
index ad774bbd49..da0eade5b2 100644
--- a/asm/osInvalICache.s
+++ b/asm/osInvalICache.s
@@ -34,13 +34,13 @@ glabel osInvalICache
 /* 006D9C 8000619C 00000000 */   nop   
 
 .L800061A0:
-/* 006DA0 800061A0 3C088000 */  lui   $t0, %hi(D_80000020) # $t0, 0x8000
+/* 006DA0 800061A0 3C088000 */  lui   $t0, 0x8000
 /* 006DA4 800061A4 010B4821 */  addu  $t1, $t0, $t3
 /* 006DA8 800061A8 2529FFE0 */  addiu $t1, $t1, -0x20
 .L800061AC:
 /* 006DAC 800061AC BD000000 */  cache 0, ($t0)
 /* 006DB0 800061B0 0109082B */  sltu  $at, $t0, $t1
 /* 006DB4 800061B4 1420FFFD */  bnez  $at, .L800061AC
-/* 006DB8 800061B8 25080020 */   addiu $t0, %lo(D_80000020) # addiu $t0, $t0, 0x20
+/* 006DB8 800061B8 25080020 */   addiu $t0, 0x20
 /* 006DBC 800061BC 03E00008 */  jr    $ra
 /* 006DC0 800061C0 00000000 */   nop   
diff --git a/asm/osWritebackDCache.s b/asm/osWritebackDCache.s
index f59c6e6ae6..820fd696bf 100644
--- a/asm/osWritebackDCache.s
+++ b/asm/osWritebackDCache.s
@@ -34,13 +34,13 @@ glabel osWritebackDCache
 /* 00530C 8000470C 00000000 */   nop   
 
 .L80004710:
-/* 005310 80004710 3C088000 */  lui   $t0, %hi(D_80000010) # $t0, 0x8000
+/* 005310 80004710 3C088000 */  lui   $t0, 0x8000
 /* 005314 80004714 010B4821 */  addu  $t1, $t0, $t3
 /* 005318 80004718 2529FFF0 */  addiu $t1, $t1, -0x10
 .L8000471C:
 /* 00531C 8000471C BD010000 */  cache 1, ($t0)
 /* 005320 80004720 0109082B */  sltu  $at, $t0, $t1
 /* 005324 80004724 1420FFFD */  bnez  $at, .L8000471C
-/* 005328 80004728 25080010 */   addiu $t0, %lo(D_80000010) # addiu $t0, $t0, 0x10
+/* 005328 80004728 25080010 */   addiu $t0, 0x10
 /* 00532C 8000472C 03E00008 */  jr    $ra
 /* 005330 80004730 00000000 */   nop   
diff --git a/asm/osWritebackDCacheAll.s b/asm/osWritebackDCacheAll.s
index a3976b395a..065f400557 100644
--- a/asm/osWritebackDCacheAll.s
+++ b/asm/osWritebackDCacheAll.s
@@ -10,7 +10,7 @@
 .balign 16
 
 glabel osWritebackDCacheAll
-/* B7D630 80106490 3C088000 */  lui   $t0, %hi(D_80000010) # $t0, 0x8000
+/* B7D630 80106490 3C088000 */  lui   $t0, 0x8000
 /* B7D634 80106494 240A2000 */  li    $t2, 8192
 /* B7D638 80106498 010A4821 */  addu  $t1, $t0, $t2
 /* B7D63C 8010649C 2529FFF0 */  addiu $t1, $t1, -0x10
@@ -18,6 +18,6 @@ glabel osWritebackDCacheAll
 /* B7D640 801064A0 BD010000 */  cache 1, ($t0)
 /* B7D644 801064A4 0109082B */  sltu  $at, $t0, $t1
 /* B7D648 801064A8 1420FFFD */  bnez  $at, .L801064A0
-/* B7D64C 801064AC 25080010 */   addiu $t0, %lo(D_80000010) # addiu $t0, $t0, 0x10
+/* B7D64C 801064AC 25080010 */   addiu $t0, 0x10
 /* B7D650 801064B0 03E00008 */  jr    $ra
 /* B7D654 801064B4 00000000 */   nop   
diff --git a/include/functions.h b/include/functions.h
index 95a23c49da..82453df409 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -160,8 +160,8 @@ OSViContext* __osViGetCurrentContext(void);
 void osStartThread(OSThread* thread);
 void osViSetYScale(f32 scale);
 void osViSetXScale(f32 value);
-void __osSetHWIntrRoutine(s32 idx, OSMesgQueue* queue, OSMesg msg);
-void __osGetHWIntrRoutine(s32 idx, OSMesgQueue** outQueue, OSMesg* outMsg);
+void __osSetHWIntrRoutine(OSHWIntr interrupt, s32 (*handler)(void), void* sp);
+void __osGetHWIntrRoutine(OSHWIntr interrupt, s32 (**handlerOut)(void), void** spOut);
 void __osSetWatchLo(u32);
 
 EnItem00* Item_DropCollectible(GlobalContext* globalCtx, Vec3f* spawnPos, s16 params);
diff --git a/include/ultra64/hardware.h b/include/ultra64/hardware.h
index 48247b4734..9ffd5c92b1 100644
--- a/include/ultra64/hardware.h
+++ b/include/ultra64/hardware.h
@@ -64,7 +64,7 @@
 
 #define PI_STATUS_BUSY 0x1
 #define PI_STATUS_IOBUSY 0x2
-#define PI_STATUS_ERROR 0x3
+#define PI_STATUS_ERROR 0x4
 
 #define PI_STATUS_RESET_CONTROLLER 0x1
 #define PI_STATUS_CLEAR_INTR 0x2
diff --git a/include/ultra64/internal.h b/include/ultra64/internal.h
index e6c9732995..647afb3d79 100644
--- a/include/ultra64/internal.h
+++ b/include/ultra64/internal.h
@@ -12,8 +12,8 @@ typedef struct {
 } OSMgrArgs; // size = 0x1C
 
 typedef struct  {
-    /* 0x00 */ OSMesgQueue* queue;
-    /* 0x04 */ OSMesg msg;
+    /* 0x00 */ s32 (*handler)(void);
+    /* 0x04 */ void* sp;
 } __osHwInt; // size = 0x08
 
 typedef struct  {
diff --git a/include/ultra64/interrupt.h b/include/ultra64/interrupt.h
index 7c669c170f..1a7ce934fb 100644
--- a/include/ultra64/interrupt.h
+++ b/include/ultra64/interrupt.h
@@ -2,5 +2,6 @@
 #define ULTRA64_INTERRUPT_H
 
 typedef u32 OSIntMask;
+typedef u32 OSHWIntr;
 
 #endif
diff --git a/include/ultra64/thread.h b/include/ultra64/thread.h
index 3d826a79e8..a1b5fc57c7 100644
--- a/include/ultra64/thread.h
+++ b/include/ultra64/thread.h
@@ -44,16 +44,16 @@ typedef struct {
 } __OSThreadprofile; // size = 0x10
 
 typedef struct OSThread {
-    /*0x00*/ struct OSThread* next;
-    /*0x04*/ OSPri priority;
-    /*0x08*/ struct OSThread** queue;
-    /*0x0C*/ struct OSThread* tlnext;
-    /*0x10*/ u16 state;
-    /*0x12*/ u16 flags;
-    /*0x14*/ OSId id;
-    /*0x18*/ s32 fp;
-    /*0x1C*/ __OSThreadprofile* thprof;
-    /*0x20*/ __OSThreadContext context;
+    /* 0x00 */ struct OSThread* next;
+    /* 0x04 */ OSPri priority;
+    /* 0x08 */ struct OSThread** queue;
+    /* 0x0C */ struct OSThread* tlnext;
+    /* 0x10 */ u16 state;
+    /* 0x12 */ u16 flags;
+    /* 0x14 */ OSId id;
+    /* 0x18 */ s32 fp;
+    /* 0x1C */ __OSThreadprofile* thprof;
+    /* 0x20 */ __OSThreadContext context;
 } OSThread; // size = 0x1B0
 
 #endif
diff --git a/include/variables.h b/include/variables.h
index 889f91d682..ff95591e77 100644
--- a/include/variables.h
+++ b/include/variables.h
@@ -14,17 +14,11 @@ extern Gfx D_060257B8[];
 extern Gfx D_0602A738[];
 extern Gfx D_0602CB48[];
 
-//extern ? D_80000004;
-//extern ? D_80000008;
-//extern ? D_8000000C;
-//extern ? D_80000010;
-//extern ? D_80000020;
-
 extern u32 osTvType;
 extern u32 osRomBase;
 extern u32 osResetType;
 extern u32 osMemSize;
-extern u8 osAppNmiBuffer[];
+extern u8 osAppNmiBuffer[0x40];
 
 extern u8 D_80009320[];
 extern u8 D_800093F0[];
diff --git a/src/libultra_boot_O1/__osGetHWIntrRoutine.c b/src/libultra_boot_O1/__osGetHWIntrRoutine.c
index 4ccfb032a3..4c182a29dc 100644
--- a/src/libultra_boot_O1/__osGetHWIntrRoutine.c
+++ b/src/libultra_boot_O1/__osGetHWIntrRoutine.c
@@ -1,7 +1,7 @@
 #include "global.h"
 #include "ultra64/internal.h"
 
-void __osGetHWIntrRoutine(s32 idx, OSMesgQueue** outQueue, OSMesg* outMsg) {
-    *outQueue = __osHwIntTable[idx].queue;
-    *outMsg = __osHwIntTable[idx].msg;
+void __osGetHWIntrRoutine(OSHWIntr interrupt, s32 (**handlerOut)(void), void** spOut) {
+    *handlerOut = __osHwIntTable[interrupt].handler;
+    *spOut = __osHwIntTable[interrupt].sp;
 }
diff --git a/src/libultra_boot_O1/__osResetGlobalIntMask.c b/src/libultra_boot_O1/__osResetGlobalIntMask.c
index c2561d712c..0e41557976 100644
--- a/src/libultra_boot_O1/__osResetGlobalIntMask.c
+++ b/src/libultra_boot_O1/__osResetGlobalIntMask.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 void __osResetGlobalIntMask(u32 mask) {
-    register s32 prevInt = __osDisableInt();
+    register u32 prevInt = __osDisableInt();
 
     __OSGlobalIntMask &= ~(mask & ~0x401);
     __osRestoreInt(prevInt);
diff --git a/src/libultra_boot_O1/__osSetGlobalIntMask.c b/src/libultra_boot_O1/__osSetGlobalIntMask.c
index 6b7895d6d4..9dab2aaf1d 100644
--- a/src/libultra_boot_O1/__osSetGlobalIntMask.c
+++ b/src/libultra_boot_O1/__osSetGlobalIntMask.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 void __osSetGlobalIntMask(u32 mask) {
-    register s32 prevInt = __osDisableInt();
+    register u32 prevInt = __osDisableInt();
 
     __OSGlobalIntMask |= mask;
     __osRestoreInt(prevInt);
diff --git a/src/libultra_boot_O1/__osSetHWIntrRoutine.c b/src/libultra_boot_O1/__osSetHWIntrRoutine.c
index b7ba0066ae..94255df336 100644
--- a/src/libultra_boot_O1/__osSetHWIntrRoutine.c
+++ b/src/libultra_boot_O1/__osSetHWIntrRoutine.c
@@ -1,11 +1,11 @@
 #include "global.h"
 #include "ultra64/internal.h"
 
-void __osSetHWIntrRoutine(s32 idx, OSMesgQueue* queue, OSMesg msg) {
-    register s32 prevInt = __osDisableInt();
+void __osSetHWIntrRoutine(OSHWIntr interrupt, s32 (*handler)(void), void* sp) {
+    register u32 prevInt = __osDisableInt();
 
-    __osHwIntTable[idx].queue = queue;
-    __osHwIntTable[idx].msg = msg;
+    __osHwIntTable[interrupt].handler = handler;
+    __osHwIntTable[interrupt].sp = sp;
 
     __osRestoreInt(prevInt);
 }
diff --git a/src/libultra_boot_O1/initialize.c b/src/libultra_boot_O1/initialize.c
index 0489067b0a..d20659298f 100644
--- a/src/libultra_boot_O1/initialize.c
+++ b/src/libultra_boot_O1/initialize.c
@@ -58,7 +58,7 @@ void __osInitialize_common(void) {
     osClockRate = (u64)((osClockRate * 3ll) / 4ull);
 
     if (!osResetType) {
-        bzero(osAppNmiBuffer, 0x40);
+        bzero(osAppNmiBuffer, sizeof(osAppNmiBuffer));
     }
 
     if (osTvType == OS_TV_PAL) {
diff --git a/src/libultra_boot_O1/osDestroyThread.c b/src/libultra_boot_O1/osDestroyThread.c
index 9d8fef2544..6f1ffff136 100644
--- a/src/libultra_boot_O1/osDestroyThread.c
+++ b/src/libultra_boot_O1/osDestroyThread.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 void osDestroyThread(OSThread* thread) {
-    register s32 prevInt = __osDisableInt();
+    register u32 prevInt = __osDisableInt();
     register OSThread* s1;
     register OSThread* s2;
 
diff --git a/src/libultra_boot_O1/osJamMesg.c b/src/libultra_boot_O1/osJamMesg.c
index 997c8fe65f..5668c476e2 100644
--- a/src/libultra_boot_O1/osJamMesg.c
+++ b/src/libultra_boot_O1/osJamMesg.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 s32 osJamMesg(OSMesgQueue* mq, OSMesg msg, s32 flag) {
-    register s32 prevInt = __osDisableInt();
+    register u32 prevInt = __osDisableInt();
 
     while (mq->validCount >= mq->msgCount) {
         if (flag == OS_MESG_BLOCK) {
diff --git a/src/libultra_boot_O1/osRecvMesg.c b/src/libultra_boot_O1/osRecvMesg.c
index d6de78adb7..0f4c83cff8 100644
--- a/src/libultra_boot_O1/osRecvMesg.c
+++ b/src/libultra_boot_O1/osRecvMesg.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 s32 osRecvMesg(OSMesgQueue* mq, OSMesg* msg, s32 flag) {
-    register s32 prevInt = __osDisableInt();
+    register u32 prevInt = __osDisableInt();
 
     while (mq->validCount == 0) {
         if (flag == OS_MESG_NOBLOCK) {
diff --git a/src/libultra_boot_O2/__osEPiRawReadIo.c b/src/libultra_boot_O2/__osEPiRawReadIo.c
index 6aa0bf0b68..513a246ee4 100644
--- a/src/libultra_boot_O2/__osEPiRawReadIo.c
+++ b/src/libultra_boot_O2/__osEPiRawReadIo.c
@@ -4,7 +4,7 @@ s32 __osEPiRawReadIo(OSPiHandle* handle, u32 devAddr, u32* data) {
     s32 status;
     OSPiHandle* curHandle;
 
-    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY | PI_STATUS_ERROR)) {
+    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY)) {
         ;
     }
 
diff --git a/src/libultra_boot_O2/__osEPiRawStartDma.c b/src/libultra_boot_O2/__osEPiRawStartDma.c
index 5ae4d9c307..c8f4de5fda 100644
--- a/src/libultra_boot_O2/__osEPiRawStartDma.c
+++ b/src/libultra_boot_O2/__osEPiRawStartDma.c
@@ -4,7 +4,7 @@ s32 __osEPiRawStartDma(OSPiHandle* handle, s32 direction, u32 cartAddr, void* dr
     s32 status;
     OSPiHandle* curHandle;
 
-    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY | PI_STATUS_ERROR)) {
+    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY)) {
         ;
     }
 
diff --git a/src/libultra_boot_O2/__osEPiRawWriteIo.c b/src/libultra_boot_O2/__osEPiRawWriteIo.c
index 7c5701e0d1..dc169ecf71 100644
--- a/src/libultra_boot_O2/__osEPiRawWriteIo.c
+++ b/src/libultra_boot_O2/__osEPiRawWriteIo.c
@@ -4,7 +4,7 @@ s32 __osEPiRawWriteIo(OSPiHandle* handle, u32 devAddr, u32 data) {
     s32 status;
     OSPiHandle* curHandle;
 
-    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY | PI_STATUS_ERROR)) {
+    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY)) {
         ;
     }
 
diff --git a/src/libultra_boot_O2/__osPiRawStartDma.c b/src/libultra_boot_O2/__osPiRawStartDma.c
index f2c0a8488e..b642b508fc 100644
--- a/src/libultra_boot_O2/__osPiRawStartDma.c
+++ b/src/libultra_boot_O2/__osPiRawStartDma.c
@@ -3,7 +3,7 @@
 s32 __osPiRawStartDma(s32 dir, u32 cartAddr, void* dramAddr, size_t size) {
     register s32 status = HW_REG(PI_STATUS_REG, u32);
 
-    while (status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY | PI_STATUS_ERROR)) {
+    while (status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY)) {
         status = HW_REG(PI_STATUS_REG, u32);
     }
 
diff --git a/src/libultra_boot_O2/osCartRomInit.c b/src/libultra_boot_O2/osCartRomInit.c
index f87d3bd051..ab54c19312 100644
--- a/src/libultra_boot_O2/osCartRomInit.c
+++ b/src/libultra_boot_O2/osCartRomInit.c
@@ -27,7 +27,7 @@ OSPiHandle* osCartRomInit(void) {
     __CartRomHandle.speed = 0;
     bzero(&__CartRomHandle.transferInfo, sizeof(__OSTranxInfo));
 
-    while (status = HW_REG(PI_STATUS_REG, u32), status & PI_STATUS_ERROR) {
+    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY)) {
         ;
     }
 
diff --git a/src/libultra_boot_O2/osDriveRomInit.c b/src/libultra_boot_O2/osDriveRomInit.c
index a9f2ea02b5..8aed46dd60 100644
--- a/src/libultra_boot_O2/osDriveRomInit.c
+++ b/src/libultra_boot_O2/osDriveRomInit.c
@@ -5,7 +5,7 @@ OSPiHandle __DriveRomHandle;
 OSPiHandle* osDriveRomInit(void) {
     register s32 status;
     register u32 a;
-    register s32 prevInt;
+    register u32 prevInt;
     static u32 D_8000AC70 = 1;
 
     __osPiGetAccess();
@@ -22,7 +22,7 @@ OSPiHandle* osDriveRomInit(void) {
     __DriveRomHandle.speed = 0;
     bzero(&__DriveRomHandle.transferInfo, sizeof(__OSTranxInfo));
 
-    while (status = HW_REG(PI_STATUS_REG, u32), status & PI_STATUS_ERROR) {
+    while (status = HW_REG(PI_STATUS_REG, u32), status & (PI_STATUS_BUSY | PI_STATUS_IOBUSY)) {
         ;
     }
 
diff --git a/src/libultra_boot_O2/osViGetNextFramebuffer.c b/src/libultra_boot_O2/osViGetNextFramebuffer.c
index aaf44ce4a9..a15a2db21c 100644
--- a/src/libultra_boot_O2/osViGetNextFramebuffer.c
+++ b/src/libultra_boot_O2/osViGetNextFramebuffer.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 void* osViGetNextFramebuffer(void) {
-    s32 prevInt = __osDisableInt();
+    u32 prevInt = __osDisableInt();
     void* buff = __osViNext->buffer;
 
     __osRestoreInt(prevInt);
diff --git a/src/libultra_boot_O2/osViSetYScale.c b/src/libultra_boot_O2/osViSetYScale.c
index 29128af768..0d7a5f9684 100644
--- a/src/libultra_boot_O2/osViSetYScale.c
+++ b/src/libultra_boot_O2/osViSetYScale.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 void osViSetYScale(f32 scale) {
-    register s32 prevInt = __osDisableInt();
+    register u32 prevInt = __osDisableInt();
 
     __osViNext->y.factor = scale;
     __osViNext->state |= 4;
diff --git a/src/libultra_boot_O2/vimgr.c b/src/libultra_boot_O2/vimgr.c
index b57b48d3b4..5be0ba2e30 100644
--- a/src/libultra_boot_O2/vimgr.c
+++ b/src/libultra_boot_O2/vimgr.c
@@ -1,21 +1,12 @@
 #include "global.h"
 #include "ultra64/internal.h"
 
-typedef struct {
-    u16 unk00;
-    u8 unk02;
-    u32 unk04;
-    u8 pad[0xC];
-    u16 unk14;
-    u16 unk16;
-} viMesgStruct;
-
 OSThread viThread;
 u8 viThreadStack[0x1000];
 OSMesgQueue viEventQueue;
 OSMesg viEventBuf[6];
-viMesgStruct viRetraceMsg;
-viMesgStruct viCounterMsg;
+OSIoMesg viRetraceMsg;
+OSIoMesg viCounterMsg;
 OSMgrArgs __osViDevMgr = { 0 };
 u32 __additional_scanline = 0;
 
@@ -30,12 +21,12 @@ void osCreateViManager(OSPri pri) {
         __osTimerServicesInit();
         __additional_scanline = 0;
         osCreateMesgQueue(&viEventQueue, viEventBuf, 5);
-        viRetraceMsg.unk00 = 13;
-        viRetraceMsg.unk02 = 0;
-        viRetraceMsg.unk04 = 0;
-        viCounterMsg.unk00 = 14;
-        viCounterMsg.unk02 = 0;
-        viCounterMsg.unk04 = 0;
+        viRetraceMsg.hdr.type = 13;
+        viRetraceMsg.hdr.pri = 0;
+        viRetraceMsg.hdr.retQueue = NULL;
+        viCounterMsg.hdr.type = 14;
+        viCounterMsg.hdr.pri = 0;
+        viCounterMsg.hdr.retQueue = NULL;
         osSetEventMesg(OS_EVENT_VI, &viEventQueue, &viRetraceMsg);
         osSetEventMesg(OS_EVENT_COUNTER, &viEventQueue, &viCounterMsg);
         newPri = -1;
@@ -68,10 +59,9 @@ void viMgrMain(void* vargs) {
     OSMgrArgs* args;
     static u16 viRetrace;
     u32 addTime;
-    viMesgStruct* mesg;
+    OSIoMesg* mesg = NULL;
     u32 temp = 0; // always 0
 
-    mesg = NULL;
     viRetrace = __osViGetCurrentContext()->retraceCount;
     if (viRetrace == 0) {
         viRetrace = 1;
@@ -81,7 +71,7 @@ void viMgrMain(void* vargs) {
 
     while (true) {
         osRecvMesg(args->eventQueue, (OSMesg)&mesg, OS_MESG_BLOCK);
-        switch (mesg->unk00) {
+        switch (mesg->hdr.type) {
             case 13:
                 __osViSwapContext();
                 viRetrace--;
diff --git a/src/libultra_code_O1/osSetTimer.c b/src/libultra_code_O1/osSetTimer.c
index a14c9b23b4..b0c4a05e91 100644
--- a/src/libultra_code_O1/osSetTimer.c
+++ b/src/libultra_code_O1/osSetTimer.c
@@ -5,7 +5,7 @@ s32 osSetTimer(OSTimer* timer, OSTime countdown, OSTime interval, OSMesgQueue* m
     OSTimer* next;
     u32 count;
     u32 value;
-    s32 prevInt;
+    u32 prevInt;
 
     timer->next = NULL;
     timer->prev = NULL;
diff --git a/src/libultra_code_O1/osStopTimer.c b/src/libultra_code_O1/osStopTimer.c
index 627d57b75d..d6d20536a1 100644
--- a/src/libultra_code_O1/osStopTimer.c
+++ b/src/libultra_code_O1/osStopTimer.c
@@ -1,7 +1,7 @@
 #include "global.h"
 
 s32 osStopTimer(OSTimer* timer) {
-    register s32 prevInt;
+    register u32 prevInt;
     OSTimer* next;
 
     if (!timer->next) {
diff --git a/undefined_syms.txt b/undefined_syms.txt
index 95cc1844eb..b2546f2f6e 100644
--- a/undefined_syms.txt
+++ b/undefined_syms.txt
@@ -1,11 +1,4 @@
 // libultra OS symbols
-D_80000000 = 0x80000000;
-D_80000002 = 0x80000002;
-D_80000004 = 0x80000004;
-D_80000008 = 0x80000008;
-D_8000000C = 0x8000000C;
-D_80000010 = 0x80000010;
-D_80000020 = 0x80000020;
 osTvType = 0x80000300;
 osRomBase = 0x80000308;
 osResetType = 0x8000030C;