Lost boot entries on Silverblue install

I installed Silverblue. I reformatted the efi partition to get it to boot properly on my uefi system. Now the system boots directly into the new silverblue install, with no boot menu, and I cannot select another OS at boot. I don’t seem to even have a rollback available.

I have one other OS installed, NixOS. grub2-mkconfig does not seem to find it.

I don’t know my way around grub. Can I manually add the other boot images? Sorry for my ignorance about grub.


If you reformatted your EFI partition, the EFI bootloader for Nix is gone.
You will have to boot a live media, chroot into your nix os system and reinstall the EFI files.

Did a brief search a found Bootloader - NixOS Wiki. It describes how to reinstall EFI bootloader for Nix under section Re-installing the bootloader

Note: NixOS assumes the ESP is mounted under /boot and that it is on the ESP that NixOS will install the files needed for the boot process for UEFI systems.

Thank you. Should I use the same efi partition as SB uses or should I use a different partition? And do you know why I don’t get a grub menu at boot time? I’ve upgraded and layered, so there should at a minimum be a fallback option. Instead, when I boot, I go directly to the gdm login screen.

I finally got a grub menu on boot. After layering a couple of packages and rebooting, the system failed to reboot and I had to force power down. When it rebooted (straight to gdm), things weren’t working like pipewire. I rebooted again, and got the grub menu for the first time with four entries listed. I chose the first, and everything is working properly.

I still have the question about the efi. I’m pursuing this on the NixOS side too, because apparently it is also particular about controlling the efi as well. The clash of rollback functionality I guess.

Yes. only one EFI partition (“ESP” - efi system partition) for your machine, even for two, three, or more systems installed.

EDIT: original post was for a different forum.

That’s what I thought. It’s just that when I installed SB it was necessary to use a new efi or it wouldn’t install.