diff --git a/artiq/firmware/runtime/rtio_mgt.rs b/artiq/firmware/runtime/rtio_mgt.rs
index f2a606d86..a8685e1bd 100644
--- a/artiq/firmware/runtime/rtio_mgt.rs
+++ b/artiq/firmware/runtime/rtio_mgt.rs
@@ -114,23 +114,21 @@ pub mod drtio {
         }
     }
 
-    fn wait_tsc_ack(linkno: u8, io: &Io) -> bool {
+    fn wait_tsc_ack(linkno: u8, io: &Io) -> Result<(), &'static str> {
         loop {
             let mut count = 0;
             if !link_rx_up(linkno) {
-                return false;
+                return Err("link went down");
             }
             count += 1;
             if count > 200 {
-                return false;
+                return Err("timeout");
             }
             io.sleep(100).unwrap();
             // TSCAck is the only aux packet that is sent spontaneously
             // by the satellite, in response to a TSC set on the RT link.
-            let pr = drtioaux::recv_link(linkno);
-            match pr {
-                Ok(Some(drtioaux::Packet::TSCAck)) => return true,
-                _ => {}
+            if let Ok(Some(drtioaux::Packet::TSCAck)) = drtioaux::recv_link(linkno) {
+                return Ok(())
             }
         }
     }
@@ -194,13 +192,13 @@ pub mod drtio {
                             set_link_up(linkno, true);
                             init_buffer_space(linkno);
                             sync_tsc(linkno);
-                            if !wait_tsc_ack(linkno, &io) {
-                                info!("[LINK#{}] remote failed to ack TSC", linkno);
+                            if wait_tsc_ack(linkno, &io).is_err() {
+                                error!("[LINK#{}] remote failed to ack TSC", linkno);
                             } else {
                                 info!("[LINK#{}] link initialization completed", linkno);
                             }
                         } else {
-                            info!("[LINK#{}] ping failed", linkno);
+                            error!("[LINK#{}] ping failed", linkno);
                         }
                     }
                 }
diff --git a/artiq/firmware/satman/main.rs b/artiq/firmware/satman/main.rs
index 2bce73681..8ca8a6b6a 100644
--- a/artiq/firmware/satman/main.rs
+++ b/artiq/firmware/satman/main.rs
@@ -298,7 +298,7 @@ pub extern fn main() -> i32 {
             }
         }
 
-        info!("link is up, switching to recovered clock");
+        info!("uplink is up, switching to recovered clock");
         si5324::siphaser::select_recovered_clock(true).expect("failed to switch clocks");
         si5324::siphaser::calibrate_skew(SIPHASER_PHASE).expect("failed to calibrate skew");
 
@@ -332,7 +332,7 @@ pub extern fn main() -> i32 {
                 rep.service();
             }
             if drtiosat_tsc_loaded() {
-                info!("TSC loaded");
+                info!("TSC loaded from uplink");
                 #[cfg(has_ad9154)]
                 {
                     if let Err(e) = board_artiq::jesd204sync::sysref_auto_rtio_align() {
@@ -343,7 +343,9 @@ pub extern fn main() -> i32 {
                     }
                 }
                 for rep in repeaters.iter() {
-                    rep.sync_tsc();
+                    if rep.sync_tsc().is_err() {
+                        error!("remote failed to ack TSC");
+                    }
                 }
                 if let Err(e) = drtioaux::send_link(0, &drtioaux::Packet::TSCAck) {
                     error!("aux packet error: {}", e);
@@ -357,7 +359,7 @@ pub extern fn main() -> i32 {
         drtiosat_reset_phy(true);
         drtiosat_reset(true);
         drtiosat_tsc_loaded();
-        info!("link is down, switching to local crystal clock");
+        info!("uplink is down, switching to local crystal clock");
         si5324::siphaser::select_recovered_clock(false).expect("failed to switch clocks");
     }
 }
diff --git a/artiq/firmware/satman/repeater.rs b/artiq/firmware/satman/repeater.rs
index 686b3acbb..d677c362e 100644
--- a/artiq/firmware/satman/repeater.rs
+++ b/artiq/firmware/satman/repeater.rs
@@ -9,7 +9,7 @@ fn rep_link_rx_up(linkno: u8) -> bool {
     }
 }
 
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, PartialEq)]
 enum RepeaterState {
     Down,
     SendPing { ping_count: u16 },
@@ -63,7 +63,7 @@ impl Repeater {
                 if rep_link_rx_up(self.repno) {
                     if let Ok(Some(drtioaux::Packet::EchoReply)) = drtioaux::recv_link(self.auxno) {
                         info!("[REP#{}] remote replied after {} packets", self.repno, ping_count);
-                        if !self.sync_tsc() {
+                        if self.sync_tsc().is_err() {
                             error!("[REP#{}] remote failed to ack TSC", self.repno);
                             self.state = RepeaterState::Failed;
                             return;
@@ -100,7 +100,11 @@ impl Repeater {
         }
     }
 
-    pub fn sync_tsc(&self) -> bool {
+    pub fn sync_tsc(&self) -> Result<(), &'static str> {
+        if self.state != RepeaterState::Up {
+            return Ok(());
+        }
+
         let repno = self.repno as usize;
         unsafe {
             (csr::DRTIOREP[repno].set_time_write)(1);
@@ -110,15 +114,15 @@ impl Repeater {
         let timeout = clock::get_ms() + 200;
         loop {
             if !rep_link_rx_up(self.repno) {
-                return false;
+                return Err("link went down");
             }
             if clock::get_ms() > timeout {
-                return false;
+                return Err("timeout");
             }
             // TSCAck is the only aux packet that is sent spontaneously
             // by the satellite, in response to a TSC set on the RT link.
             if let Ok(Some(drtioaux::Packet::TSCAck)) = drtioaux::recv_link(self.auxno) {
-                return true;
+                return Ok(());
             }
         }
     }
@@ -130,5 +134,5 @@ impl Repeater {
 
     pub fn service(&self) { }
 
-    pub fn sync_tsc(&self) { }
+    pub fn sync_tsc(&self) -> Result<(), &'static str> { Ok(()) }
 }