diff --git a/rust/kernel/auxiliary.rs b/rust/kernel/auxiliary.rs
index 4e83f9e27d78..df2c97423dcc 100644
--- a/rust/kernel/auxiliary.rs
+++ b/rust/kernel/auxiliary.rs
@@ -369,6 +369,10 @@ unsafe impl Send for Device {}
 // (i.e. `Device<Normal>) are thread safe.
 unsafe impl Sync for Device {}
 
+// SAFETY: Same as `Device<Normal>` -- the underlying `struct auxiliary_device` is the same;
+// `Bound` is a zero-sized type-state marker that does not affect thread safety.
+unsafe impl Sync for Device<device::Bound> {}
+
 /// Wrapper that stores a [`TypeId`] alongside the registration data for runtime type checking.
 #[repr(C)]
 #[pin_data]