Comment 622 for bug 1734147

On Thu, Feb 14, 2019 at 10:44:34PM -0000, Marek Hák wrote:
> The output of 'efibootmgr -v' showed me where the EFI partition is, but
> I have no idea where it's mounted or how to get to it.

> Boot0004* ubuntu HD(2,GPT,83484852-541d-401e-
> 84e7-6e6e8549496a,0x1f4800,0x82000)/File(\EFI\ubuntu\shimx64.efi)

OK, this should be either sda2 or sdb2 depending on which order your disks
were detected. So you should be able to do sudo mount /dev/sda2 /boot/efi
to mount it (or /dev/sdb2, depending).

Then once you have replaced that grubx64.efi with the one that allows
booting unsigned kernels, you should run 'sudo umount /boot/efi' to make
sure the disk is cleanly unmounted. After this, you should have a
secureboot-enabled grub on the internal disk which allows you to boot to a
different unsigned kernel on the flash drive in order to reset the firmware

> Thanks again for any help! I'd really love to sort this out :)

Sorry this is such a mess.