Confirmed that this works for Debian Jessie (at the time of writing Fedora doesn't compile the kernel with the 64/32 EFI thunk).
However what doesn't work is any driver which requires access the device's ROM, such as the AMD Radeon graphics. The access to that ends when the boot loader ends the EFI boot services stage. By then either the bootloader (or the kernel started in EFI stub mode) needs to have copied out the ROM into RAM.
At the time of writing it's simply impossible to get to that point. Grub's linuxefi command conflates secure boot and a EFI stub boot, so if you are booting on a EFI with no support for secure boot it fails with a checksum error. Both Refind and Gummiboot currently have issues booting Linux in EFI stub mode. The radeon driver people NAKed a patch to take the ROM in a file, which would have at least been a work-around.
The result is no way to run Linux from EFI beyond text mode on 2006-era MacBooks. Note that you may not be able to easily run Linux from BIOS emulation mode either: only Bootcamp v4 lets you install non-Windows BIOS-using operating systems, so if you upgraded MacOS beyond that you'll need to reinstall MacOS.
All in all trying to get Linux working as an alternative to an out-of-support MacOS has been two months of continuing disappointment.
Power management, mobile and firmware developer on Linux. Security developer at Aurora. Ex-biologist. mjg59 on Twitter. Content here should not be interpreted as the opinion of my employer. Also on Mastodon.
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Date: 2015-01-31 07:50 am (UTC)However what doesn't work is any driver which requires access the device's ROM, such as the AMD Radeon graphics. The access to that ends when the boot loader ends the EFI boot services stage. By then either the bootloader (or the kernel started in EFI stub mode) needs to have copied out the ROM into RAM.
At the time of writing it's simply impossible to get to that point. Grub's linuxefi command conflates secure boot and a EFI stub boot, so if you are booting on a EFI with no support for secure boot it fails with a checksum error. Both Refind and Gummiboot currently have issues booting Linux in EFI stub mode. The radeon driver people NAKed a patch to take the ROM in a file, which would have at least been a work-around.
The result is no way to run Linux from EFI beyond text mode on 2006-era MacBooks. Note that you may not be able to easily run Linux from BIOS emulation mode either: only Bootcamp v4 lets you install non-Windows BIOS-using operating systems, so if you upgraded MacOS beyond that you'll need to reinstall MacOS.
All in all trying to get Linux working as an alternative to an out-of-support MacOS has been two months of continuing disappointment.