Ubuntu fail on boot after Windows 10 update (20H2)

I'm using a dual-boot os (Windows 10 and Ubuntu), after I update the Windows to the latest update 20H2 the GRUB isn't showing on reboot else display these errors

Malformed security header
Failed to read header: Invalid Parameter
Failed to load images: Invalid Parameter
start_img() returned Invalid Parameter

then the Windows 10 start.

I found some similar problems HERE. Has anyone encountered this issue before?

1 Answer

I had a similiar issue with my dual boot setup:

• W10 on one SSD
• ArchLinux on another SSD
• UEFI GRUB on Linux disk
• Mobo booting from the UEFI/Linux disk although in my case the update failed (and for like the n-th time already, drives me crazy tbh...)

After the failed update GRUB went down. I would only get a black screen with GRUB letters on it.

My fix was all about recreating GRUB as you would do when installing Linux to get the dual-boot in the first place.

1. boot the system from a live-USB instance
2. mount all the partitions in correct mount-points (not sure if that step was necessary though, probably not...)
3. reinstall GRUB with grub-install in the way applicable to your setup (UEFI vs BIOS)
4. reconfigure GRUB with grub-mkconfig

grub-mkconfig succesfully located both Linux and Windows and generated correct entries.

After that I exited the live-USB system, rebooted and everything was back and working.