diff --git a/opt/libgba/mgba.c b/opt/libgba/mgba.c
index 22a4f0851..51787661d 100644
--- a/opt/libgba/mgba.c
+++ b/opt/libgba/mgba.c
@@ -32,7 +32,7 @@
 #define REG_DEBUG_FLAGS (vu16*) 0x4FFF700
 #define REG_DEBUG_STRING (char*) 0x4FFF600
 
-ssize_t mgba_stdout_write(struct _reent* r __attribute__((unused)), int fd __attribute__((unused)), const char* ptr, size_t len) {
+ssize_t mgba_stdout_write(struct _reent* r __attribute__((unused)), void* fd __attribute__((unused)), const char* ptr, size_t len) {
 	if (len > 0x100) {
 		len = 0x100;
 	}
@@ -41,7 +41,7 @@ ssize_t mgba_stdout_write(struct _reent* r __attribute__((unused)), int fd __att
 	return len;
 }
 
-ssize_t mgba_stderr_write(struct _reent* r __attribute__((unused)), int fd __attribute__((unused)), const char* ptr, size_t len) {
+ssize_t mgba_stderr_write(struct _reent* r __attribute__((unused)), void* fd __attribute__((unused)), const char* ptr, size_t len) {
 	if (len > 0x100) {
 		len = 0x100;
 	}