UEFI dual boot broken since (Fedora and/or Windows) update

Hello all,

I don’t use my secondary system (laptop) that much, so when I do, I always perform a system update. It’s a dual boot system consisting of Fedora 34 and Windows 10 on a SATA SSD (/dev/sda). This week, I performed both Windows- and Fedora updates. The latter contained (among other things) kernel 5.13.4.

The next time I (re)booted the system, GRUB came up as expected; showing the new kernel on top of the list. I chose the Windows bootloader and got an error about unable to find a Windows boot file. I’m sorry; I didn’t write it down to post in this message. Fedora started normally using GRUB.

I then used a Windows installation stick to repair its boot mechanism - and that worked. Too well - since Fedora and GRUB are now no longer starting.

Trying to repair the old, working dual-boot situation, I read about and performed a chroot from a live-system. Even the LUKS part worked as expected. Finally running os-prober in the chroot, I got another error (probably the cause of this problem): cannot find a GRUB file for /dev/sda3 (which is the Windows partition). It then proceeds to add a boot option for entering the UEFI setup.

Having followed the Fedora documentation on the subject, and having failed - How can I re-install GRUB with both Fedora and Windows being available?

Thank you very much,
Frans-Willem

Not really solved the issue, but saved the day by completely reinstalling Fedora 34.

The installer correctly handled placing of the bootloader and making a true dual-boot system, once again.

Case closed.

Thanks for reading,
FWieP