Thanks Thomas for the explanation :) Repacking with xorriso it's an option and i don't understand why your workflow isn't the default behaviour of xorriso. I send the message here because i guess live-build should change the way of building the EFI iso, don't you think? Otherwise everyone who needs to add a second partition like me, we will fall on the same issue.
On my side, i solved the issue, but i would like to help the community to saving other people's time. R. On Wed, Mar 18, 2020 at 1:47 PM Thomas Schmitt <scdbac...@gmx.net> wrote: > Hi, > > cagnulein wrote: > > > http://robertoviola.cloud/2020/03/18/add-a-data-partition-to-a-live-usb-iso/ > > The partition table of the clonzilla ISO seems to be BIOS-only with > partition offset 16. > The table of the urbackup ISO looks like ready for BIOS and EFI with > partition offset 16, too. > > (From the partition offset i conclude both were made by xorriso.) > > Debian-Live ISOs have the same layout as the urbackup ISO. > Invented by Matthew J. Garret for SYSLINUX program "isohybrid". > > > > I don't understand why the first partition has 0x00 as partition type. > > That's because in the partition layout of "isohybrid", the EFI System > Partition is inside the ISO 9660 partition. > This is forbidden by UEFI specs. But the specs also say that partition > type 0x00 shall be ignored (i assume as mark of an unused partition slot). > So Matthew J. Garret used type 0x00 when he invented that layout. > (He also added an invalid GPT partition table to his invention.) > > There are better ways to equip an ISO by an EFI System Partition. See: > https://lists.debian.org/debian-cd/2019/07/msg00007.html > > > Back to the web link above: > > Changing partition type 0x00 to 0x0b "W95 FAT32" bears the risk to break > EFI booting from USB stick, because it makes invalid the table entry > of the EFI partition (0xef). The effect depends on the EFI firmware > implementation. > > If it is important to get rid of the type 0x00 for partition 1 and > repacking by xorriso is not an option, then i advise to do: > - create a new partition of the same size as partition 2 with type 0xef > if possible to have two 0xef, else 0x83, > - flatly copy the content of partition 2 to the new partition range, > - delete partition 2, > - give partition 3 type 0xef if this was not possible on creation, > - change the type of partition 1 from 0x00 to 0x83 ("Linux"). > > Now the EFI partition 3 is outside of partition 1. So both may have > a non-zero type without violating the UEFI specs. > > > Have a nice day :) > > Thomas > >
