diff --git a/include/functions.h b/include/functions.h
index b4c7c03a..b9c6d3ec 100644
--- a/include/functions.h
+++ b/include/functions.h
@@ -22,6 +22,7 @@ void fn_80045F74(s16, s32);
 s32 fn_800578E4(void);
 void fn_1_26C(void);
 
+void HuDecodeData(void *src, void *dst, u32 size, int decode_type);
 
 void HuMemInitAll(void);
 void *HuMemInit(void *ptr, s32 size);