Re: [gentoo-user] Verify uefi installation

[Mick]

On Sunday, 22 September 2019 05:22:02 BST Adam Carter wrote:
> After updating the BIOS on my motherboard, the system will no longer boot.
> The NVME drive is still recognised in the BIOS and set to the the primary
> boot device. However, when i originally installed the system (and assuming
> I remember correctly) the boot order setting in the BIOS showed something
> about the operating system as part of the M2 drive entry, which it doesn't
> now. The original BIOS is not available for download, so I tried a couple
> of others, including the oldest available, but no change.
>
> I can boot from a usb drive and mount the vfat /dev/nvme0n1p1 partition.
> The usual kernel files are there, as is EFI/gentoo/grubx64.efi
>
> What can I do to verify the OS installation?

The UEFI menu will present you with a list of bootable devices.  The UEFI 
firmware will probe connected devices to find anything which can provide 
booting (from hard drives, to USB devices, to network ports) and list them.  
Among those the grubx64.efi ought to be listed as an available option.

If not, you can use the efibootmgr to set it as a bootable image in the UEFI 
firmware.  Boot with a Live-USB and follow this page:

https://wiki.gentoo.org/wiki/Efibootmgr

Of course, grubx64.efi will only boot OS kernels it has been configured to 
boot with.  So, make sure while you're in the Live-USB environment and have 
chrooted into your installation, you run 'grub-mkconfig -o /boot/grub/
grub.cfg' or what is appropriate for your boot filesystem.

HTH.
-- 
Regards,
Mick