diff --git a/include/functions.h b/include/functions.h
index 63ee51708d..65514ca8e0 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -479,7 +479,7 @@ void* osViGetCurrentFramebuffer(void);
 s32 __osSpSetPc(void* data);
 // void __osVoiceContWrite4(void);
 void __osGetHWIntrRoutine(s32 idx, OSMesgQueue** outQueue, OSMesg* outMsg);
-// void __osSetHWIntrRoutine(void);
+void __osSetHWIntrRoutine(s32 idx, OSMesgQueue* queue, OSMesg msg);
 u32 __osGetWatchLo(void);
 void __osSetWatchLo(u32 value);
 f32 fmodf(f32 dividend, f32 divisor);
diff --git a/src/libultra/os/sethwinterrupt.c b/src/libultra/os/sethwinterrupt.c
index 86dfd2c649..6ba72be7a1 100644
--- a/src/libultra/os/sethwinterrupt.c
+++ b/src/libultra/os/sethwinterrupt.c
@@ -1,3 +1,10 @@
 #include "global.h"
 
-#pragma GLOBAL_ASM("asm/non_matchings/boot/sethwinterrupt/__osSetHWIntrRoutine.s")
+void __osSetHWIntrRoutine(s32 idx, OSMesgQueue* queue, OSMesg msg) {
+    register s32 prevInt = __osDisableInt();
+
+    __osHwIntTable[idx].queue = queue;
+    __osHwIntTable[idx].msg = msg;
+
+    __osRestoreInt(prevInt);
+}