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Broken UEFI implementations: Difference between revisions
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= Apple =
Apple firmwares have a couple of funky things going on
=== There's additional UI presented mixed in with BDS ===
The "option key" boot screen and such are basically between BootNext/BootOrder and any other BDS menus and such. In effect they are the BDS menus, but they do a lot of non-BDS things. So basically BootNext and BootOrder can override the normal boot selection from that menu without you ever seeing it, but the things that show up in that menu aren't strictly governed by Boot#### variables.
Instead, Apple requires a HFS+ filesystem to be present to use as the ESP, and it has to be set up in a particular way:
# Your bootloader has to exist as /EFI/${vendor}/whatever.efi and has to be blessed with hfs-bless.
# there needs to be a pixmap of the text label you want, named /EFI/${vendor}/.disk_label
# There needs to be a pixmap of the logo you want as /.VolumeIcon.icns .
# You need /System/Library/CoreServices/SystemVersion.plist to exist and describe your OS.
# /mach_kernel must exist.
The [http://www.codon.org.uk/~mjg59/mactel-boot/ mactel-boot] utility can be used to set up these things.
=== CDs are wild and crazy ===
For CDs to boot without using Boot#### variables or the CSM, they need to be Apple Partition Map formatted, i.e. the format Apple has used since they derived it from the format NeXT used when they bought them. This means to make a disc that works on EFI+Apple+BIOS you need to actually /execute/ the APM header signature on BIOS machines. Thankfully that's pretty safe, but it's a little squicky in your head. [http://www.syslinux.org/wiki/index.php/The_Syslinux_Project syslinux]]'s "isohybrid" utility has had this ability to build this sort of image since version 4.05 .
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