Problems During Boot
Problem: Boot fails with message "Unable to import rpool." and drops to an (initramfs) prompt.
Cause: The initiramfs image is using stale ZFS cache files.
Fix: Regenerate the cache files and initramfs image.
At the (initramfs) prompt type zpool import rpool and then exit to continue booting normally. Run the following commands as root to regenerate the caches and initramfs image:
zpool set cachefile= rpool
update-initramfs -u -k all
After running the commands reboot the computer to verify a successful boot.
Problem: Boot fails with message "Gave up waiting for root file system device." and drops to an (initramfs) prompt.
Cause: The initiramfs image is using device names instead of UUIDs.
Fix: Regenerate the initramfs image so it references UUIDs.
At the (initramfs) prompt type blkid and note which device the root file system is located on (such as /dev/sda2) then reboot the computer and press E at the GRUB screen. Correct the root=/dev/sda2 line to reflect what the device name is and press Ctrl+X to boot the system. If it fails a second time then type blkid again to see if the device name has changed and repeat the process with the new name. It may take a few tries if the device name is changing every time. Once you've booted successfully log in and become root. Verify that only UUIDs are used in /etc/fstab and then run the following commands to regenerate the initramfs image:
update-initramfs -u -k all
grub-mkconfig
update-grub
After running the commands reboot the computer and press E at the GRUB screen to verify that the root= line is using a UUID instead of a device name.
Problem: Grub menu is not displayed, possibly with an "out of sync" message, but system boots normally.
Cause: Grub is using an invalid video mode or hardware does not support it.
Fix: Disable the graphical Grub menu.
Boot the system normally and then log in and become root. Run the following commands:
update-initramfs -u -k all
sed -i 's/#GRUB_TERMINAL=console/GRUB_TERMINAL=console/g' /etc/default/grub
update-grub
After running the commands reboot the computer and verify that the issue is resolved.
Problem: Some EFI-based systems can't boot from non-default file names.
Cause: Early or buggy EFI implementation.
Fix: Copy the EFI boot loader to a standard name.
Boot into your installed Debian system using the build-in EFI shell or a USB drive with shellx64.efi copied to it.
mkdir /boot/efi/EFI/boot
cp -p /boot/efi/EFI/debian/grubx64.efi /boot/efi/EFI/boot/bootx64.efi
After running the commands reboot the computer and verify that the issue is resolved. You will have to re-run the copy command manually if you update your Grub version.
Optionally configure the update_debian.sh script to automatically update the copy of Grub:
echo 'cp -p /boot/efi/EFI/debian/grubx64.efi /boot/efi/EFI/boot/bootx64.efi' \
>> /opt/update_debian.sh
Problem: No display, or frozen display after booting. System has an Nvidia video card.
Cause: Nouveau can't properly control the video hardware.
Fix: Disable Nouveau and install the Nvidia drivers.
At the Grub menu press E and add nomodeset to the end of the linux /boot/ line after quiet then press Ctrl+X to continue booting. If the system comes up normally then install the Nvidia drivers.
apt-get install -y nvidia-cuda-toolkit nvidia-detect \
nvidia-kernel-dkms nvidia-smi nvidia-driver nvidia-settings
After running the commands reboot the computer and verify that the issue is resolved. The changes made in Grub's boot menu are not persistent across reboots.