grub2-mkconfig error

10B2 · n00b Joined: 28 May 2013 Posts: 65

I use a Sony Vaio tap 11 with windows 8 preinstalled.
Have created 3 partitions for gentoo, boot (ext2), swap and the major linux partition (ext4), where I installed gentoo.
I am trying to dual boot in EFI mode with GRUB2.
The EFI partition set by the producer is the 3rd.
Mounted this latter partition onto /boot/efi.
Executed grub2-install; no problem.
Then I run 'grub2-mkconfig -o /boot/efi/EFI/GRUB2/grub.cfg ---->/usr/sbin/grub2-probe: error: failed to get canonical path of 'PARTUUID=...'
and the grub2 configuration file is not generated.

I can anyway boot from grub-2.00 console, which starts by default in uefi mode on my pc, using genkernel and initramfs.

I would believe that this might be related with partitions naming and filesystems. Indeed I noticed these issues:

- when booting in UEFI or legacy mode from usb drive, my partitions are named sdaX. When booting without usb they are renamed sdbX. This the reason why I modified fstab changing sda into sdb.

- in dmesg I get this error:EXT2-fs (sdb9) error: couldn't mount because of unsopported optional feature. May be this error would disappear
if unchecked ext2 filesystem in kernel, as I did with ext3 fs (which provided similar error). But since created a linux boot partition which is ext2, am not sure if I can without ext2 fs. What about changing the linux boot partition filesystem into efi? After all I mount in /boot/efi the original EFI partition of my pc.

- Once I would be able to boot gentoo from grub2 interface (not console), then I would add the menuentry for dual booting windows8

Thanks in advance

ct85711 · Veteran Joined: 27 Sep 2005 Posts: 1791

One thing with UEFI, is that you only need 1 efi partition for the entire system, reguardless which drive it is on. Last I saw, windows 8 defaults to installing with EFI, so it would have created a efi partition already. So you do not need to make any other efi partitions. In general efi partitions are formated as a fat32 drive (excluding for OSX, and linux in general doesn't have to be, but generaly is). So you are perfectly fine to reusing the windows efi partition along with linux; it won't affect any files windows made, as both the linux efi and windows can coexist right next to each other happily. I can't say what effects the system will have if it encounters 2 seperate efi partitions. Grub2 should see the windows efi (assuming you are only using 1 efi partition), and automaticaly add that for you, so you don't have to add it in later.

Otherwise, I would recommend you DO compile in ext2 fs support into the kernel along with ext4 (for the /boot partition). The big reason is that a ext4 drive with all the default options enabled is not able to be mounted by ext2/3 (from my understanding, converting a ext2/3 drive into ext4 enables all except 1 option which has to be set when the partition is set). Another thing that will help you out on the unsupported optional feature error, is add this to your /etc/default/grub file.

10B2 · n00b Joined: 28 May 2013 Posts: 65

Still not working...not able to generate gub.cfg file:
error: failed to get canonical path of 'PARTUUID=...'

fidel · Guru Joined: 16 Jul 2004 Posts: 407 Location: CH

Has there been any progress so far? I now can't generate a grub.cfg any more, the same error message appears. This is even the case after having udev creating symlinks to /dev/disk/by-partuuid/.

bpkent · n00b Joined: 17 Feb 2011 Posts: 14

Had a similar issue, when stracing grub2-probe I saw that it looked in current working directory for PARTUUID=<foo>. Symlinking the /dev/sd<bar> device to $PWD/PARTUUID=<foo> resulted in grub2-probe succeeding, as did grub2-mkconfig. My build_kernel script now has: