Hi, Florian Pelz wrote: > For x86_64 iso images, the Macbook does *not dismiss*. It gets stuck > in the lightgray startup screen forever without showing a menu with > the drives to boot from, except for the Debian ISO image, for which a > menu is shown with an »EFI partition« that runs a bootloader when > chosen.
So the problem might be during the inspection of the EFI partition whether it is worth to be offered for booting. Comparing the output of program "strings" from both bootx64.efi files, i see in the Debian file text about Secure Boot, which are not in the Guix file: SecureBoot SetupMode ... Secure Boot forbids loading module from %s ... grub_efi_secure_boot Older Debian netinst maybe ? ... digging in my collection ... The youngest without "Secure" in its bootx64.efi is debian-7.7.0-amd64-netinst.iso You could check whether this hangs like Guix. Debian's own ISO archive of 7.7.0 only offers CD-1 as jigdo. Probably with the same EFI equipment. But let's google ... http://ftp.riken.go.jp/Linux/debian/debian-cdimage/archive/7.7.0/amd64/iso-cd/debian-7.7.0-amd64-netinst.iso It matches my old copy. 232,783,872 bytes. SHA512: 5cb6e4fea55fbb5173f90c3a545b843c6c193e29c3aa32b3306c9bbdfb1ad6a6a36ae8be50e91af9d03d5f21c472bd05d04d3508172e0b519e76714333c7c74b Have a nice day :) Thomas