Today’s CPLUG Free Your Machine brought new challenges in the form of UEFI laptops with Windows 8. (On the plus side, though, GPT means no more worries about already having 4 OEM-created partitions).
First, all Windows 8 systems needed fast boot disabled. Then we needed to disable Secure Boot. Some firmware setup utilities were more cooperative than others, and in several cases we had to just recommend installing Linux in a VM (since Wubi doesn’t support UEFI).
Finally, on two laptops (an HP Envy and a Toshiba Satellite), Linux Mint and
GRUB would install correctly but the machine would still boot directly to
Windows, and there was no firmware setup option to specify the path to the
grubx64.efi file. I ended up getting these to boot to GRUB, then to either
Linux Mint or Windows 8, as follows.
Disclaimer: I’m reconstructing these commands from memory a few minutes after the fact, so no guarantees they’re exactly correct, much less that they will work on any other system.
Boot to a Linux LiveCD/USB again and mount the EFI partition, then move the
Windows bootmgfw.efi aside and replace it with a copy of GRUB’s
grubx64.efi:
# mkdir efi
# mount /dev/sda2 efi
# cd efi/EFI/Microsoft/Boot/
# mv bootmgfw{,-real}.efi
# cp -a ../../linuxmint/grubx64.efi bootmgfw.efi
Now on boot, GRUB should run and start Linux Mint. From the installed system,
add an entry to GRUB that chainloads Windows via the moved-aside file by
adding the following to /etc/grub.d/40_custom (adapted from
here):
menuentry "Windows 8" --class windows --class os {
insmod part_gpt
insmod chain
set root=(hd0,gpt2)
chainload /EFI/Microsoft/Boot/bootmgfw-real.efi
}
then run update-grub to regenerate the configuration. With any luck, GRUB
will now offer a choice between Linux Mint and Windows 8, and both will work!