[SOLVED] The devil is in the details
Hi fellow Slackers
GRUB2 (aka 2.00), as opposed to GRUB (aka GRUB Legacy or 0.97), supports UEFI out of the box. grub.efi (or grubx64.efi) are the EFI binaries which can be generated either by GRUB2 or GRUB legacy.
efibootmgr works by accessing the efi_vars. I can not access them, since I'm on 32 bit Slackware. (the chicken and egg thing: even having booted with EFI it's like i booted from the install CD). That is also the reason I'm not using ELILO, since the 32 bit ELILO EFI binary can not load a 32 bit kernel. GRUB can, as a matter of fact I'm writing this from such a box.
Being unable to "normally" make the firmware aware of my bootloaders (cd: /sys/firmware/efi/vars/: No such file or directory), I have 3 options, the third one being too immoral to discuss (involves using the dark side of the Force).
1. (aka the correct one): Manually adding the entry using bcfg. The problem is, this Tianocore-based EFI seems to have shell 1.0, which does not have bcfg.
2. (aka the practical one): copy grubx64.efi to \EFI\bootx64.efi (overwriting anything there) which is what i finally did.
Next things to do with this laptop: enable Bumblebee (I compiled everything but the modded Mesa: it loads some games saying it loads the nvidia driver, but crashes sometimes) and the touchpad (sadly, xinput --list-props 14 | grep Capabilities reports "Synaptics Capabilities (314): 1, 0, 0, 1, 1, 1, 1", which means I do not have a physical right button). If you own such a Lenovo Z480, do not attempt to use the NVIDIA drivers without bumblebee: you will get a black screen and a nice inverted screen when returning to open source drivers.
GRUB2 works very well, it's skinnable, and it is possible to manually configure it. I'll test the firmware shell (which I just downloaded) later.
In short, if you want to install x86 32-bit Slackware to a new x86_64 capable laptop with EFI and a GPT disk, use GRUB2.
If you are using x86_64 64 bit Slackware, just have a relocatable EFI enabled 3.6 or later kernel and overwrite bootx64.efi with it (assuming you're using only Slackware). Or use ELILO. (do have in mind that ELILO can only boot Linux, but having access to efi_vars you might also be able to run efibootmgr to properly set it up together with other bootloaders).
Last edited by folkenfanel; 12-12-2012 at 12:30 PM.
Reason: mark as solved?