diff --git a/flake.nix b/flake.nix
index 52ba789..2107881 100644
--- a/flake.nix
+++ b/flake.nix
@@ -134,7 +134,7 @@
         cargoLock = { 
           lockFile = src/Cargo.lock;
           outputHashes = {
-            "libasync-0.0.0" = "sha256-7qRHEHg+CXqqZSLgV4j9XLrLj6mlaeXzCZ8eFkRa0U8=";
+            "libasync-0.0.0" = "sha256-xuwesRrQiccopPTCkwGqQxld74X74q7EVsKIrE0zirc=";
           };
         };
 
diff --git a/src/Cargo.lock b/src/Cargo.lock
index 2b11062..88db5db 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -219,7 +219,7 @@ dependencies = [
 [[package]]
 name = "libasync"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#56c27e98e4fc2bd719d26abaa98a7628c395b9c0"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#605c8f73a60cf41a6e2d535c5850933d3154e935"
 dependencies = [
  "embedded-hal",
  "libcortex_a9",
@@ -251,7 +251,7 @@ dependencies = [
 [[package]]
 name = "libboard_zynq"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#56c27e98e4fc2bd719d26abaa98a7628c395b9c0"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#605c8f73a60cf41a6e2d535c5850933d3154e935"
 dependencies = [
  "bit_field",
  "embedded-hal",
@@ -276,7 +276,7 @@ dependencies = [
 [[package]]
 name = "libconfig"
 version = "0.1.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#56c27e98e4fc2bd719d26abaa98a7628c395b9c0"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#605c8f73a60cf41a6e2d535c5850933d3154e935"
 dependencies = [
  "core_io",
  "fatfs",
@@ -287,7 +287,7 @@ dependencies = [
 [[package]]
 name = "libcortex_a9"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#56c27e98e4fc2bd719d26abaa98a7628c395b9c0"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#605c8f73a60cf41a6e2d535c5850933d3154e935"
 dependencies = [
  "bit_field",
  "libregister",
@@ -303,7 +303,7 @@ checksum = "33a33a362ce288760ec6a508b94caaec573ae7d3bbbd91b87aa0bad4456839db"
 [[package]]
 name = "libregister"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#56c27e98e4fc2bd719d26abaa98a7628c395b9c0"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#605c8f73a60cf41a6e2d535c5850933d3154e935"
 dependencies = [
  "bit_field",
  "vcell",
@@ -313,7 +313,7 @@ dependencies = [
 [[package]]
 name = "libsupport_zynq"
 version = "0.0.0"
-source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#56c27e98e4fc2bd719d26abaa98a7628c395b9c0"
+source = "git+https://git.m-labs.hk/M-Labs/zynq-rs.git#605c8f73a60cf41a6e2d535c5850933d3154e935"
 dependencies = [
  "cc",
  "compiler_builtins",
diff --git a/src/runtime/src/moninj.rs b/src/runtime/src/moninj.rs
index a95777d..5b13606 100644
--- a/src/runtime/src/moninj.rs
+++ b/src/runtime/src/moninj.rs
@@ -20,7 +20,7 @@ use crate::proto_async::*;
 pub enum Error {
     NetworkError(smoltcp::Error),
     UnexpectedPattern,
-    UnrecognizedPacket,
+    UnrecognizedPacket
 }
 
 pub type Result<T> = core::result::Result<T, Error>;
@@ -58,45 +58,47 @@ enum DeviceMessage {
 #[cfg(has_drtio)]
 mod remote_moninj {
     use super::*;
-    use libboard_artiq::drtioaux;
+    use libboard_artiq::drtioaux_async;
     use crate::rtio_mgt::drtio;
     use log::error;
 
-    pub fn read_probe(aux_mutex: &Rc<Mutex<bool>>, timer: GlobalTimer, linkno: u8, destination: u8, channel: i32, probe: i8) -> i64 {
-        let reply = task::block_on(drtio::aux_transact(aux_mutex, linkno, &drtioaux::Packet::MonitorRequest { 
+    pub async fn read_probe(aux_mutex: &Rc<Mutex<bool>>, timer: GlobalTimer, linkno: u8, destination: u8, channel: i32, probe: i8) -> i64 {
+        let reply = drtio::aux_transact(aux_mutex, linkno, &drtioaux_async::Packet::MonitorRequest { 
             destination: destination,
             channel: channel as _,
             probe: probe as _},
-            timer));
+            timer).await;
         match reply {
-            Ok(drtioaux::Packet::MonitorReply { value }) => return value as i64,
+            Ok(drtioaux_async::Packet::MonitorReply { value }) => return value as i64,
             Ok(packet) => error!("received unexpected aux packet: {:?}", packet),
+            Err("link went down") => { debug!("link is down"); },
             Err(e) => error!("aux packet error ({})", e)
         }
         0
     }
 
-    pub fn inject(aux_mutex: &Rc<Mutex<bool>>, _timer: GlobalTimer, linkno: u8, destination: u8, channel: i32, overrd: i8, value: i8) {
+    pub async fn inject(aux_mutex: &Rc<Mutex<bool>>, _timer: GlobalTimer, linkno: u8, destination: u8, channel: i32, overrd: i8, value: i8) {
         let _lock = aux_mutex.lock();
-        drtioaux::send(linkno, &drtioaux::Packet::InjectionRequest {
+        drtioaux_async::send(linkno, &drtioaux_async::Packet::InjectionRequest {
             destination: destination,
             channel: channel as _,
             overrd: overrd as _,
             value: value as _
-        }).unwrap();
+        }).await.unwrap();
     }
 
-    pub fn read_injection_status(aux_mutex: &Rc<Mutex<bool>>, timer: GlobalTimer, linkno: u8, destination: u8, channel: i32, overrd: i8) -> i8 {
-        let reply = task::block_on(drtio::aux_transact(aux_mutex, 
+    pub async fn read_injection_status(aux_mutex: &Rc<Mutex<bool>>, timer: GlobalTimer, linkno: u8, destination: u8, channel: i32, overrd: i8) -> i8 {
+        let reply = drtio::aux_transact(aux_mutex, 
             linkno, 
-            &drtioaux::Packet::InjectionStatusRequest {
+            &drtioaux_async::Packet::InjectionStatusRequest {
                 destination: destination,
                 channel: channel as _,
                 overrd: overrd as _},
-            timer));
+            timer).await;
         match reply {
-            Ok(drtioaux::Packet::InjectionStatusReply { value }) => return value as i8,
+            Ok(drtioaux_async::Packet::InjectionStatusReply { value }) => return value as i8,
             Ok(packet) => error!("received unexpected aux packet: {:?}", packet),
+            Err("link went down") => { debug!("link is down"); },
             Err(e) => error!("aux packet error ({})", e)
         }
         0
@@ -142,7 +144,7 @@ macro_rules! dispatch {
             local_moninj::$func(channel.into(), $($param, )*)
         } else {
             let linkno = hop - 1 as u8;
-            remote_moninj::$func($aux_mutex, $timer, linkno, destination, channel, $($param, )*)
+            remote_moninj::$func($aux_mutex, $timer, linkno, destination, channel, $($param, )*).await
         }
     }}
 }
@@ -163,20 +165,21 @@ async fn handle_connection(stream: &TcpStream, timer: GlobalTimer,
 
     let mut probe_watch_list: BTreeMap<(i32, i8), Option<i64>> = BTreeMap::new();
     let mut inject_watch_list: BTreeMap<(i32, i8), Option<i8>> = BTreeMap::new();
-    let mut next_check = Milliseconds(0);
+    let mut next_check = timer.get_time();
+    let timeout = |next_check: Milliseconds| -> nb::Result<(), Void> {
+        if timer.get_time() < next_check {
+            Err(nb::Error::WouldBlock)
+        } else {
+            Ok(())
+        }
+    };
     loop {
         // TODO: we don't need fuse() here.
         // remove after https://github.com/rust-lang/futures-rs/issues/1989 lands
         let read_message_f = read_i8(&stream).fuse();
         let next_check_c = next_check.clone();
-        let timeout = || -> nb::Result<(), Void> {
-            if timer.get_time() < next_check_c {
-                Err(nb::Error::WouldBlock)
-            } else {
-                Ok(())
-            }
-        };
-        let timeout_f = block_async!(timeout()).fuse();
+
+        let timeout_f = block_async!(timeout(next_check_c)).fuse();
         pin_mut!(read_message_f, timeout_f);
         select_biased! {
             message = read_message_f => {
@@ -246,7 +249,7 @@ async fn handle_connection(stream: &TcpStream, timer: GlobalTimer,
                         *previous = Some(current);
                     }
                 }
-                next_check = next_check + Milliseconds(200);
+                next_check = timer.get_time() + Milliseconds(200);
             }
         }
     }
diff --git a/src/runtime/src/rtio_mgt.rs b/src/runtime/src/rtio_mgt.rs
index d72a902..a77f2e0 100644
--- a/src/runtime/src/rtio_mgt.rs
+++ b/src/runtime/src/rtio_mgt.rs
@@ -49,7 +49,10 @@ pub mod drtio {
 
     pub async fn aux_transact(aux_mutex: &Mutex<bool>, linkno: u8, request: &Packet,
             timer: GlobalTimer) -> Result<Packet, &'static str> {
-        let _lock = aux_mutex.lock();
+        if !link_rx_up(linkno).await {
+            return Err("link went down");
+        }
+        let _lock = aux_mutex.async_lock().await;
         drtioaux_async::send(linkno, request).await.unwrap();
         recv_aux_timeout(linkno, 200, timer).await
     }
@@ -88,7 +91,7 @@ pub mod drtio {
     }
 
     async fn sync_tsc(aux_mutex: &Rc<Mutex<bool>>, linkno: u8, timer: GlobalTimer) -> Result<(), &'static str> {
-        let _lock = aux_mutex.lock();
+        let _lock = aux_mutex.async_lock().await;
 
         unsafe {
             (csr::DRTIO[linkno as usize].set_time_write)(1);
@@ -142,7 +145,7 @@ pub mod drtio {
     }
 
     async fn process_unsolicited_aux(aux_mutex: &Rc<Mutex<bool>>, linkno: u8) {
-        let _lock = aux_mutex.lock();
+        let _lock = aux_mutex.async_lock().await;
         match drtioaux_async::recv(linkno).await {
             Ok(Some(packet)) => warn!("[LINK#{}] unsolicited aux packet: {:?}", linkno, packet),
             Ok(None) => (),