Without oflag=direct, dd copies the ISO into the page cache at high speed, the
status=progress counter races to ~100%, then appears to hang at the end while
the slow USB drains and conv=fsync flushes — looking frozen when it is still
writing. write-usb.sh now writes with oflag=direct (honest device-level
progress) and falls back to a cached write if the bridge rejects O_DIRECT;
build.sh's dd hint and explanation are updated to match.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Amir Alexander Abdelbaki
0e04a7cada