diff --git a/src/platform/redox/mod.rs b/src/platform/redox/mod.rs
index 38860e0d81..6521d5b818 100644
--- a/src/platform/redox/mod.rs
+++ b/src/platform/redox/mod.rs
@@ -1426,6 +1426,11 @@ impl Pal for Sys {
         Ok(())
     }
 
+    fn syncfs(fd: c_int) -> Result<()> {
+        // Red Bear filesystem I/O is synchronous — fsync(fd) is sufficient.
+        Self::fsync(fd)
+    }
+
     fn timer_create(clock_id: clockid_t, evp: &sigevent, mut timerid: Out<timer_t>) -> Result<()> {
         if evp.sigev_notify == SIGEV_THREAD {
             if evp.sigev_notify_function.is_none() {