Hi, Mike Kupfer wrote: > I'm booting using EFI.
So this could be a problem with GRUB about how it leaves the USB stick after having loaded kernel and initrd from it. The volatility of success and failure still gives me riddles. But if you can reproduce failure within a bearable number of tries, then it could be indeed a topic for grub-devel mailing list. > > How does the stick behave if you plug it into a running GNU/Linux system ? > > Any problem messages in the log ? Is it usable as storage device ? > If I plug the stick into the laptop when it's running, the stick is > mounted okay. [...] didn't notice anything odd, but then I'm not familiar > with the contents of a hybrid image ISO. They have about the best verification support you can wish for. https://www.debian.org/CD/faq/#verify proposes to learn the number of sectors /sbin/isosize -x <device> and to then compute the checksum of that amount of data dd if=<device> count=<sector count> bs=2048 | sha512sum which is to be compared with the .iso image's line in file SHA512SUMS from where you downloaded the ISO. Have a nice day :) Thomas
