Best way to recover boot entry after BIOS/firmware update?

Ask Fedora
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1

I will update the bios/firmware of my laptop soon, which will likely delete my boot entry in the bios.

What is the best way of recovering it? Should I just reinstall GRUB?

I use Fedora 43 with a fully encrypted disk (without Secure Boot), Btrfs (default installation, no manual changes). How do I chroot into this to reinstall GRUB?
(Have only done this on Ubuntu on a “regular” Ext4 installation yet.)

2

See this guide in the Fedora docs.

That said, you should be able to restore the boot entry just by running efibootmgr from the live environment, no need for the chroot.

First: run efibootmgr with no arguments to see the current boot entries.

Second: create the boot entry with something like:

efibootmgr --create --index 0001 --disk /dev/nvme0n1 --part 1 --loader \\EFI\\fedora\\shimx64.efi

This assumes your EFI partition is /dev/nvme0n1p1. Change the --disk and --part arguments appropriately if not. Also, if index 0001 was already present when you checked the current boot entries, choose an unused index.

3

Before updating, make notes of the current entries using efibootmgr and (belt & suspenders!) the system BIOS tools. I find it faster to use the BIOS tools on my Dell systems, but with an old iMac I use efibootmgr from a Live USB environment.

4

Thanks!

BootCurrent: 0000
Timeout: 0 seconds
BootOrder: 0000,0002,0001,0013,0014,0015,0016,0017,0018
Boot0000* Fedora        HD(1,GPT,cb896b75-f1e2-4b91-93fe-74ac57e1b176,0x800,0x12c000)/\EFI\fedora\shimx64.efi
Boot0001* Windows Boot Manager  HD(1,GPT,cb896b75-f1e2-4b91-93fe-74ac57e1b176,0x800,0x12c000)/\EFI\Microsoft\Boot\bootmgfw.efi57494e444f5753000100000088000000780000004200430044004f0042004a004500430054003d007b00390064006500610038003600320063002d0035006300640064002d0034006500370030002d0061006300630031002d006600330032006200330034003400640034003700390035007d00000000000100000010000000040000007fff0400
Boot0002* Kubuntu       HD(1,GPT,47eb0262-d558-41a4-8c8b-9966c02623ad,0x1000,0x96000)/\EFI\ubuntu\shimx64.efi
Boot0010  Setup FvFile(721c8b66-426c-4e86-8e99-3457c46ab0b9)
Boot0011  Boot Menu     FvFile(86488440-41bb-42c7-93ac-450fbf7766bf)
Boot0012  UEFI Diagnostics      FvFile(f8397897-e203-4a62-b977-9e7e5d94d91b)
Boot0013* NVMe: VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,001c199932d94c4eae9aa0b6e98eb8a4)
Boot0014* USB HDD:      VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,33e821aaaf33bc4789bd419f88c50803)
Boot0015* PCI LAN:      VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,78a84aaf2b2afc4ea79cf5cc8f3d3803)
Boot0016* USB FDD:      VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,6ff015a28830b543a8b8641009461e49)
Boot0017* USB CD:       VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,86701296aa5a7848b66cd49dd3ba6a55)
Boot0018* USB LAN:      VenMsg(bc7838d2-0f82-4d60-8316-c068ee79d25b,e854bca4cae7704ca322b00da0376322)
Boot0019* Reinstall Windows from Cloud  FvFile(3edbaac4-5017-4870-8cc4-721f9ef1974f)2d004100700070000000

Fedora is the current one, previously I had Windows & Kubuntu (for testing), but I removed them.

My partitions:

/dev/nvme0n1p3: UUID="c8c8762a-ff5c-4fb0-8c3b-c03fef298df4" TYPE="crypto_LUKS" PARTUUID="fe521dfa-9c8f-4d0f-ac8d-01f2ba9d8c4d"
/dev/nvme0n1p1: UUID="1414-88CD" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI System Partition" PARTUUID="cb896b75-f1e2-4b91-93fe-74ac57e1b176"
/dev/nvme0n1p2: UUID="d09647cb-7b32-4890-8b0e-ab2cd71bd18c" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="e41c080d-9b2f-4975-8f46-c14f49b56ef9"
/dev/mapper/luks-c8c8762a-ff5c-4fb0-8c3b-c03fef298df4: LABEL="fedora" UUID="6153a88e-556d-4dc9-a031-327ea83259fd" UUID_SUB="8c221345-3765-4974-a2ec-4fc5a71ea9c2" BLOCK_SIZE="4096" TYPE="btrfs"
/dev/zram0: LABEL="zram0" UUID="be55cc28-57c8-4771-9e4e-6d3c70b0af25" TYPE="swap"