diff --git a/include/usersystemlib_kernel.h b/include/usersystemlib_kernel.h
index 28a1a61..3a33189 100644
--- a/include/usersystemlib_kernel.h
+++ b/include/usersystemlib_kernel.h
@@ -223,12 +223,12 @@ void *sceKernelMemcpy(void *dst, const void *src, SceSize size);
  * See http://www.cplusplus.com/reference/cstring/memset/
  *
  * @param dst Pointer to the memory block to fill.
- * @param val Value to be set, casted to the u8 type.
+ * @param val Value to be set.
  * @param size Number of bytes to be set.
  *
  * @return Value of dst.
  */
-void *sceKernelMemset(void *dst, s32 val, SceSize size);
+void *sceKernelMemset(void *dst, s8 val, SceSize size);
 
 /** @} */
 
diff --git a/src/usersystemlib/mem.c b/src/usersystemlib/mem.c
index a49bd41..74296ee 100644
--- a/src/usersystemlib/mem.c
+++ b/src/usersystemlib/mem.c
@@ -18,12 +18,12 @@ void *sceKernelMemcpy(void *dst, const void *src, SceSize size)
 }
 
 // FIXME: naive, not reversed!
-void *sceKernelMemset(void *dst, s32 val, SceSize size)
+void *sceKernelMemset(void *dst, s8 val, SceSize size)
 {
     u8 *dst8 = (u8*)dst;
 
     while (size--) {
-        *(dst8++) = (u8)val;
+        *(dst8++) = val;
     }
 
     return dst;