Gitea runs each matrix entry as its own task, so build-image.yaml's `max-parallel: 1` never serialized the two editions -- both builds started at once on the fedora:host runner and corrupted each other's global anaconda/livemedia-creator state (/mnt/sysroot, /mnt/sysimage, loop and device-mapper devices), surfacing as bootctl failing with "Couldn't find EFI system partition" even though the dish's EFI partition was fine. build-image.sh now takes a host-wide flock around livemedia-creator, and under the lock first clears any stale mount/dm/loop device a previously failed build left behind. Verified on the runner: both editions launched concurrently now run serially under the lock and build successfully. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>