Hi, i wrote: > > And as said previously, BIOS does not expect any partitions.
Pascal Hambourg wrote: > experience taught me that many BIOS implementations wrongly > expect an MBR partition entry with the boot flag set in order to boot from > the disk. You are right (and those firmwares are wrong). I had to introduce a special option in xorriso in order to cater for this: https://savannah.gnu.org/bugs/?46716 http://lists.gnu.org/archive/html/bug-xorriso/2015-12/threads.html with the final conclusion described in https://lists.gnu.org/archive/html/bug-grub/2016-03/msg00087.html Summary: - Boot flag on MBR partition of type 0xEE is bad on several EFI implementations. - No MBR partition with boot flag is bad on some very few BIOS implementations. - Compromise is to set the boot flag on a dummy partition of type 0x00. This is barely UEFI-compliant because the specs say that a partition of type 0x00 shall be regarded as non-existent. Debian isohybrids for BIOS do not have this problem because MBR partition 1 has the boot flag set, anyway. But grub-mkrescue ISOs might be in need of xorrisofs option --mbr-force-bootable if the owner suffers from one of those rare BIOSes. (It was decided that from the view of GRUB this is a workaround for a specs violation by the firmware. iSo --mbr-force-bootable is not applied by default.) Have a nice day :) Thomas
