On 23/04/2024 00:49, Thomas Schmitt wrote:
This aims at an undocumented habit of EFI implementations to look in any FAT filesystem for a \EFI\BOOT directory with a suitable BOOT*.EFI file and to start it, if found. (Officially documented is to look in FAT filesystems of partitions with MBR type 0xEF or GPT type GUID C12A7328-F81F-11D2-BA4B-00A0C93EC93B.)
Out of curiosity, does the requirement of specific GUID exist for removable drives? A USB drive may be formatted without partition table.
I am in doubts if any user will really benefit from UEFI implementations strictly following the spec. Making a bootable media is harder for regular users, chance of unintentional action is low, it is unlikely an obstacle for attackers trying to force users to boot a compromised image.
So just mount the ISO: and copy its content to the mounted USB stick.
7z and bsdtar can extract content of ISO files without mounting images.
