diff --git a/flake.nix b/flake.nix
index 4912a076b..fd11e0422 100644
--- a/flake.nix
+++ b/flake.nix
@@ -486,7 +486,7 @@
               read LOCK_OK
 
               artiq_flash -t kc705 -H rpi-1 -d ${packages.x86_64-linux.artiq-board-kc705-nist_clock}
-              sleep 15
+              sleep 30
 
               export ARTIQ_ROOT=`python -c "import artiq; print(artiq.__path__[0])"`/examples/kc705_nist_clock
               export ARTIQ_LOW_LATENCY=1