diff --git a/other/bootstrap_daemon/docker/update-sha256 b/other/bootstrap_daemon/docker/update-sha256
index 8bf6e0d8..6f352f38 100755
--- a/other/bootstrap_daemon/docker/update-sha256
+++ b/other/bootstrap_daemon/docker/update-sha256
@@ -3,7 +3,7 @@
 set -eux
 
 docker_build() {
-  docker build -f other/bootstrap_daemon/docker/Dockerfile -t toxchat/bootstrap-node .
+  DOCKER_BUILDKIT=1 docker build --progress=plain -f other/bootstrap_daemon/docker/Dockerfile -t toxchat/bootstrap-node .
 }
 
 # Run Docker build once. If it succeeds, we're good.
@@ -12,12 +12,11 @@ if docker_build; then
 fi
 
 # We're not good. Run it again, but now capture the output.
-OUTPUT=$(docker_build || true 2>&1)
+OUTPUT=$(docker_build 2>&1 || true)
 
 if echo "$OUTPUT" | grep '/usr/local/bin/tox-bootstrapd: FAILED'; then
   # This is a checksum warning, so we need to update it.
-  IMAGE=$(echo "$OUTPUT" | grep '^ ---> [0-9a-f]*$' | grep -o '[0-9a-f]*$' | tail -n1)
-  docker run --rm "$IMAGE" sha256sum /usr/local/bin/tox-bootstrapd >other/bootstrap_daemon/docker/tox-bootstrapd.sha256
+  echo "$OUTPUT" | grep -Eo '[0-9a-f]{64}  /usr/local/bin/tox-bootstrapd' | tail -n1 >other/bootstrap_daemon/docker/tox-bootstrapd.sha256
 fi
 
 # Run once last time to complete the build.