diff --git a/artiq/firmware/runtime/mgmt.rs b/artiq/firmware/runtime/mgmt.rs
index 0962fcc97..95ac3870b 100644
--- a/artiq/firmware/runtime/mgmt.rs
+++ b/artiq/firmware/runtime/mgmt.rs
@@ -333,7 +333,7 @@ mod remote_coremgmt {
                     buffer.extend(&value[..length as usize]);
 
                     if last {
-                        Reply::ConfigData(&value[..length as usize]).write_to(stream)?;
+                        Reply::ConfigData(&buffer).write_to(stream)?;
                         return Ok(());
                     }