On Thu, Mar 04, 2021 at 05:18:18PM +0100, Marco Kühnel wrote: > after the recent update to grub2/202+dfsg1-20+deb10u4, during boot the > mentioned error is thrown. After that, boot continues but lightdm cannot be > started anymore. > This only happens on my laptop containing two bootable hard disks. The > separate boot partitions share /boot/efi and from the second hard disk its > Ubuntu > installation still boots flawlessly. For the Debian installation, /boot and > /boot/efi are both on /dev/sda, but by default the laptop boots from /dev/sdb.
What do you mean by "the laptop boots from /dev/sdb"? If your EFI System Partition is on /dev/sda1, then by definition that's where the boot loader lives, unless you're doing something else odd. Do you just mean that your root file system is on /dev/sdb? > Tried: grub-install /dev/sda In UEFI mode, grub-install ignores the device name you give it, and always installs to the EFI System Partition on /boot/efi. Could you please post the full output of "grub-install --debug"? -- Colin Watson (he/him) [cjwat...@debian.org]