diff --git a/include/functions.h b/include/functions.h
index 87e3ba2be..2ed3bf63c 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -386,7 +386,7 @@ s32 __osContChannelReset(OSMesgQueue* mq, s32 count);
 s32 __osVoiceSetADConverter(OSMesgQueue* mq, s32 port, u8 arg2); 
 s32 osAiSetFrequency(u32 frequency);
 s32 __osContRamRead(OSMesgQueue* mq, s32 channel, u16 address, u8* buffer);
-s32 __osVoiceContWrite20(OSMesgQueue*, s32, u8, u8*);
+s32 __osVoiceContWrite20(OSMesgQueue* mq, s32 port, u16 arg2, u8 dst[20]);
 u8 __osContAddressCrc(u16 addr);
 u8 __osContDataCrc(u8* data);
 OSThread* __osGetActiveQueue(void);
@@ -470,7 +470,7 @@ s32 osVoiceControlGain(OSVoiceHandle* hd, s32 analog, s32 digital);
 s32 osVoiceStartReadData(OSVoiceHandle* hd);
 u32* osViGetCurrentFramebuffer(void);
 s32 __osSpSetPc(void* pc);
-s32 __osVoiceContWrite4(OSMesgQueue* mq, s32 port, u16 arg2, u8* dst[4]);
+s32 __osVoiceContWrite4(OSMesgQueue* mq, s32 port, u16 arg2, u8 dst[4]);
 void __osGetHWIntrRoutine(s32 idx, OSMesgQueue** outQueue, OSMesg* outMsg);
 void __osSetHWIntrRoutine(s32 idx, OSMesgQueue* queue, OSMesg msg);
 u32 __osGetWatchLo(void);
diff --git a/src/libultra/voice/voicecontwrite20.c b/src/libultra/voice/voicecontwrite20.c
index 5ca3560ed..9eba371c6 100644
--- a/src/libultra/voice/voicecontwrite20.c
+++ b/src/libultra/voice/voicecontwrite20.c
@@ -1,3 +1,68 @@
 #include "global.h"
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/voicecontwrite20/__osVoiceContWrite20.s")
+s32 __osVoiceContWrite20(OSMesgQueue* mq, s32 port, u16 arg2, u8 dst[20]) {
+    s32 errorCode;
+    u8 status;
+    u8* ptr;
+    s32 retryCount = 2;
+    s32 i;
+    u8 temp_s2;
+
+    __osSiGetAccess();
+
+    do {
+
+        ptr = (u8*)&__osPfsPifRam;
+
+        if ((__osContLastCmd != 0xA) || (port != D_80097FB0)) {
+            __osContLastCmd = 0xA;
+            D_80097FB0 = port;
+
+            for (i = 0; i < port; i++, *ptr++ = 0) {
+                ;
+            }
+
+            __osPfsPifRam.pifstatus = CONT_CMD_READ_BUTTON;
+
+            ptr[0] = 0xFF;
+            ptr[1] = 0x17;
+            ptr[2] = 1;
+            ptr[3] = 0xA;
+            ptr[0x1A] = 0xFF;
+            ptr[0x1B] = 0xFE;
+        } else {
+            ptr = (u8*)&__osPfsPifRam + port;
+        }
+
+        ptr[4] = arg2 >> 3;
+        ptr[5] = __osContAddressCrc(arg2) | (arg2 << 5);
+
+        bcopy(dst, &ptr[6], 20);
+        
+        __osSiRawStartDma(OS_WRITE, &__osPfsPifRam);
+        temp_s2 = __osVoiceContDataCrc(dst, 20);
+        osRecvMesg(mq, NULL, OS_MESG_BLOCK);
+        __osSiRawStartDma(OS_READ, &__osPfsPifRam);
+        osRecvMesg(mq, NULL, OS_MESG_BLOCK);
+
+        errorCode = (ptr[2] & 0xC0) >> 4;
+
+        if (errorCode == 0) {
+            if (ptr[0x1A] != ((void)0, temp_s2)) {
+                errorCode = __osVoiceGetStatus(mq, port, &status);
+                if (errorCode != 0) {
+                    break;
+                }
+
+                errorCode = CONT_ERR_CONTRFAIL;
+            }
+        } else {
+            errorCode = CONT_ERR_NO_CONTROLLER;
+        }
+
+    } while ((errorCode == CONT_ERR_CONTRFAIL) && (retryCount-- >= 0));
+
+    __osSiRelAccess();
+
+    return errorCode;
+}
diff --git a/src/libultra/voice/voicecontwrite4.c b/src/libultra/voice/voicecontwrite4.c
index 09158c043..8e1af6bd8 100644
--- a/src/libultra/voice/voicecontwrite4.c
+++ b/src/libultra/voice/voicecontwrite4.c
@@ -1,6 +1,6 @@
 #include "global.h"
 
-s32 __osVoiceContWrite4(OSMesgQueue* mq, s32 port, u16 arg2, u8* dst[4]) {
+s32 __osVoiceContWrite4(OSMesgQueue* mq, s32 port, u16 arg2, u8 dst[4]) {
     s32 errorCode;
     u8 status;
     u8* ptr;
@@ -48,7 +48,7 @@ s32 __osVoiceContWrite4(OSMesgQueue* mq, s32 port, u16 arg2, u8* dst[4]) {
         errorCode = (ptr[2] & 0xC0) >> 4;
 
         if (errorCode == 0) {
-            if (ptr[0xA] != (0, temp_s2)) {
+            if (ptr[0xA] != ((void)0, temp_s2)) {
                 errorCode = __osVoiceGetStatus(mq, port, &status);
                 if (errorCode != 0) {
                     break;