diff --git a/nac3artiq/src/codegen.rs b/nac3artiq/src/codegen.rs
index b57156ce..04a1a9af 100644
--- a/nac3artiq/src/codegen.rs
+++ b/nac3artiq/src/codegen.rs
@@ -584,7 +584,7 @@ fn rpc_codegen_callback_fn<'ctx>(
             let buffer = ArraySliceValue::from_ptr_val(buffer, buffer_size, None);
 
             for (offset, byte) in
-                [0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 1u8].into_iter().enumerate()
+                [1u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8, 0u8].into_iter().enumerate()
             {
                 let pbuffer = unsafe {
                     buffer.ptr_offset_unchecked(