diff --git a/photon/libc/sys/magenta/fio.c b/photon/libc/sys/magenta/fio.c
index d6c8efb..d66df45 100644
--- a/photon/libc/sys/magenta/fio.c
+++ b/photon/libc/sys/magenta/fio.c
@@ -51,7 +51,8 @@ void __fio_init(mx_handle_t in, mx_handle_t out, mx_handle_t err)
 int __fio_fopen(const char *path, const char *mode, struct __io_file *fp)
 {
     mx_handle_t h = MX_NULL_HANDLE;
-    mx_status_t stat = mx_file_open(MX_NULL_HANDLE, path, 0, &h);
+    mx_flags_t flags = flags_from_mode(mode);
+    mx_status_t stat = mx_file_open(MX_NULL_HANDLE, path, flags, &h);
 
     if (stat != MX_OK) {
         return -1;