my XBOOT is booting fine from 500 GB WD Elements USB 3.0.
Menu is also coming up.
BUT: when starting one of the ISOs on HDD, ERROR 25: Disk read error appears.
Test with QEMU works, though, so it's probably not an ISO-failure!
Also copying ISO-file to root is not helpful.
All working without probs with identical files from USB-stick.