diff --git a/nixos/modules/update-deployment b/nixos/modules/update-deployment
index 306bb882ef98aedeb16c25b150fb00bcd5507ff1..1f0415a7fdbb23c557a023a37c896df2f6a45428 100755
--- a/nixos/modules/update-deployment
+++ b/nixos/modules/update-deployment
@@ -51,8 +51,10 @@ fi
 git -C "${CHECKOUT}" reset --hard "origin/${BRANCH}"
 
 # If we happen to be on the local grid then fix the undefined key.
-KEY="$(cat /etc/ssh/authorized_keys.d/vagrant)"
-sed -i "s_undefined_\"${KEY}\"_" "${CHECKOUT}"/morph/grid/${GRIDNAME}/public-keys/users.nix
+if [ "${GRIDNAME}" = "local" ]; then
+    KEY="$(cat /etc/ssh/authorized_keys.d/vagrant)"
+    sed -i "s_undefined_\"${KEY}\"_" "${CHECKOUT}"/morph/grid/${GRIDNAME}/public-keys/users.nix
+fi
 
 # Compute a log message explaining what we're doing.
 LOG_MESSAGE="$(date --iso-8601=seconds) $(git -C "${CHECKOUT}" rev-parse HEAD)"