diff --git a/artiq/firmware/runtime/rtio_mgt.rs b/artiq/firmware/runtime/rtio_mgt.rs
index 41dbcb42a..92aaaf66a 100644
--- a/artiq/firmware/runtime/rtio_mgt.rs
+++ b/artiq/firmware/runtime/rtio_mgt.rs
@@ -220,15 +220,15 @@ pub mod drtio {
                                 destination_set_up(routing_table, up_destinations, destination, false),
                             Ok(drtioaux::Packet::DestinationOkReply) => (),
                             Ok(drtioaux::Packet::DestinationSequenceErrorReply { channel }) => {
-                                error!("[DEST#{}] RTIO sequence error involving channel {} 0x{:04x}", destination, resolve_channel_name(channel as u32), channel);
+                                error!("[DEST#{}] RTIO sequence error involving channel 0x{:04x}:{}", destination, channel, resolve_channel_name(channel as u32));
                                 unsafe { SEEN_ASYNC_ERRORS |= ASYNC_ERROR_SEQUENCE_ERROR };
                             }
                             Ok(drtioaux::Packet::DestinationCollisionReply { channel }) => {
-                                error!("[DEST#{}] RTIO collision involving channel {} 0x{:04x}", destination, resolve_channel_name(channel as u32), channel);
+                                error!("[DEST#{}] RTIO collision involving channel 0x{:04x}:{}", destination, channel, resolve_channel_name(channel as u32));
                                 unsafe { SEEN_ASYNC_ERRORS |= ASYNC_ERROR_COLLISION };
                             }
                             Ok(drtioaux::Packet::DestinationBusyReply { channel }) => {
-                                error!("[DEST#{}] RTIO busy error involving channel {} 0x{:04x}", destination, resolve_channel_name(channel as u32), channel);
+                                error!("[DEST#{}] RTIO busy error involving channel 0x{:04x}:{}", destination, channel, resolve_channel_name(channel as u32));
                                 unsafe { SEEN_ASYNC_ERRORS |= ASYNC_ERROR_BUSY };
                             }
                             Ok(packet) => error!("[DEST#{}] received unexpected aux packet: {:?}", destination, packet),
@@ -355,15 +355,15 @@ fn async_error_thread(io: Io) {
             let errors = csr::rtio_core::async_error_read();
             if errors & ASYNC_ERROR_COLLISION != 0 {
                 let channel = csr::rtio_core::collision_channel_read();
-                error!("RTIO collision involving channel {}:{}", channel, resolve_channel_name(channel as u32));
+                error!("RTIO collision involving channel 0x{:04x}:{}", channel, resolve_channel_name(channel as u32));
             }
             if errors & ASYNC_ERROR_BUSY != 0 {
                 let channel = csr::rtio_core::busy_channel_read();
-                error!("RTIO busy error involving channel {}:{}", channel, resolve_channel_name(channel as u32));
+                error!("RTIO busy error involving channel 0x{:04x}:{}", channel, resolve_channel_name(channel as u32));
             }
             if errors & ASYNC_ERROR_SEQUENCE_ERROR != 0 {
                 let channel = csr::rtio_core::sequence_error_channel_read();
-                error!("RTIO sequence error involving channel {}:{}", channel, resolve_channel_name(channel as u32));
+                error!("RTIO sequence error involving channel 0x{:04x}:{}", channel, resolve_channel_name(channel as u32));
             }
             SEEN_ASYNC_ERRORS = errors;
             csr::rtio_core::async_error_write(errors);
diff --git a/artiq/firmware/runtime/session.rs b/artiq/firmware/runtime/session.rs
index e942d7bd9..c0f009a96 100644
--- a/artiq/firmware/runtime/session.rs
+++ b/artiq/firmware/runtime/session.rs
@@ -457,7 +457,7 @@ fn process_kern_message(io: &Io, aux_mutex: &Mutex,
                             } else {
                                 let msg = str::from_utf8(unsafe { slice::from_raw_parts(exn.message.as_ptr(), exn.message.len()) })
                                     .unwrap()
-                                    .replace("{rtio_channel_info:0}", &format!("{}:{}", exn.param[0], resolve_channel_name(exn.param[0] as u32)));
+                                    .replace("{rtio_channel_info:0}", &format!("0x{:04x}:{}", exn.param[0], resolve_channel_name(exn.param[0] as u32)));
                                 Some(eh::eh_artiq::Exception {
                                     id: exn.id,
                                     file: exn.file,