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Chris M Language
Asked: 2024-09-21 20:46:19 +0800 CST

Dual boot, Ubuntu not booting after Win11 update

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I've looked for a recent answer I can understand (absolute novice) but nothing seemed to address my specific problem.

system summary

My system is set to boot Ubuntu first (see setup screen image). The second boot is Windows 11 home, fully updated as of 2024/09/21.

Each time I switch on I get the following:

Failed to open \EFI\UBUNTU\grubx64.efi - Not Found

Failed to load image __: Not Found

start_image() returned Not Found, falling back to default loader

Failed to open \EFI\UBUNTU\grubx64.efi - Not Found

Failed to load image __: Not Found

start_image() returned Not Found

photo of boot fail message

It then boots into Windows.

Please explain like I'm a kid, how I can make my laptop boot into Ubuntu again?

I should add that I bought it a while back as-is, and I have no install disk for either Windows or Ubuntu.

dual-boot

1 Answers

  1. Best Answer

    A recent windows update invalidated the grub secure boot signature. This would both prevent grub from booting windows and (after a bios update or bios key invalidation) may prevent grub itself from booting. This should not be an issue if your grub is up to date. Turning off secure boot would allow grub to boot long enough to update linux and then re-enable secure boot.

    Having said that, I would expect different error messages from this problem. The former windows error would be something like "Verifying shim SBAT data failed: Security Policy Violation Something has gone seriously wrong: SBAT self-check failed: Security Policy Violation". If grub itself fails secure boot, the symptoms would vary by bios but may include mention of secure boot failure or just skipping grub entirely without any error. You can try disabling secure boot and see if that fixes it.

    However, the "not found" errors make me suspect your EFI boot partition has been corrupted. The easiest way to fix this is to use something like refind to bypass the damaged grub and then run grub-install or the Ubuntu live disk to try to do a boot repair.

    Ubuntu has a boot repair utility at https://help.ubuntu.com/community/Boot-Repair

    Glancing at other answers linked here in comments, I think a lot of them are too old and possibly not relevant anymore.

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