Failed to boot shim.efi but boots grub anyway, File(.䥗䑎坏S)

So this is the strangest thing ever happened to me.

Long story short: In a dual-boot system, BIOS gets updated from within Windows 10. Result, grub2 does not appear anymore and can’t load Fedora38.

I boot into the hidden system, reinstall grub and shim, then try efibootmgr command but it stucks at creating a new boot entry in UEFI. So I can perfectly boot in my Fedora system but only manually selecting the /EFI/fedora/shimx64.efi.

As efibootmgr failed, I decided to go into Windows and use bcdedit /set {bootmgr} path \EFI\fedora\shimx64.efi in cmd.exe (not powershell, it does not work there). This add a boot option to my UEFI BIOS, nice.

Now the strange part: I can dual-boot again! On laptop boot I see my grub screen with Fedora and Windows Boot Manager, but!
As soon as the laptop boots, on top left it shows an error:

Failed to load \EFI\fedora\坏S - Invalid Parameter
Failer to load image : Invalid Parameter
start_image() returnet Invalid Parameter, falling back to default loader

After 2 seconds, the errors disappear and I see the grub2 screen and proceed normally.

To investigate, I booted into Fedora and executed efibootmgr

My first boot entry is, strangely:

Boot0000* Fedora	HD(1,GPT,243e1c4e-ddba-4d32-b384-e382ef6d177b,0x800,0x82000)/File(\EFI\fedora\shimx64.efi) File(.䥗䑎坏S)

Reinstalling shim * did not help. Can someone suggest me what the hell bcdedit wrote to that path? Because launching bcdedit on Windows shows me the correct \EFI\fedora\shimx64.efi…

I suggest you create a new entry using efibootmgr pehaps using a label other than “Fedora”.

In your entry

Boot0000* Fedora	HD(1,GPT,243e1c4e-ddba-4d32-b384-e382ef6d177b,0x800,0x82000)/File(\EFI\fedora\shimx64.efi) File(.䥗䑎坏S)

The part File(.䥗䑎坏S) seems to confuse the shim loader

1 Like

Yes I did, as we were talking about that here and indeed now everything is smooth again.

Probably the fact that a “fedora” already existed and the fact that I used windows to create a boot entry might have created those strange characters. Still, very funny to have seen that lol