Hi, i wrote: > > I would need to know how the MBR and the subsequent data blocks > > are produced.
Samuel Thibault wrote: > The build log is available on > https://people.debian.org/~sthibault/hurd-i386/installer/cdimage/daily/debian-cd.log This mentions grub_embed two times when xorriso gets its name and when xorriso reports to have used it. But i see no hint how this files gets created. It would be interesting to know which documentation and which GRUB modules lead to that binary. I googled for "grub_embed". The best match was your changelog entry from 2014: Add usb key boot support for kfreebsd & hurd images. This needs another grub image, grub_embed, which has to be very small. Add x86-image script, similar to efi-image script, with factorized grub-cpmodules part, to build minimal grub images with iso9660 and biosdisk support, and put GRUB modules on the ISO image. I was unable to find kFreeBSD ISOs which have an MBR. Would that "x86-image script" explain more ? (https://sources.debian.net/src/debian-cd/unstable/ throws "Internal Server Error", so i cannot currently explore debian-cd myself.) > xorriso is version 1.3.2 It's fully sufficient, although quite old. > > > > with horizontal and vertical roll-over > > Do you see the same effects in your tests ? > Yes. And also with linux/kfreebsd images. Not with amd64 (can't get i386 to boot with -bios OVMF.fd on my amd64 machine). https://cdimage.debian.org/debian-cd/current/amd64/iso-cd/debian-9.0.0-amd64-netinst.iso With SeaBIOS, ISOLINUX is in charge and works fine. With OVMF, GRUB2 is in charge and works fine. The kFreeBSD mini ISOs i have indeed show the same display problem as the newest Hurd NETINST. But debian-7.9.0-kfreebsd-amd64-netinst.iso is OK with SeaBIOS. It has GRUB 1.99 (which is a GRUB2 before its first official release). So currently it looks like the problem is with GRUB 2.02 on (Sea)BIOS. I will ponder how to reproduce it with grub-mkrescue. Have a nice day :) Thomas
