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Asked: 2019-01-13 02:45:41 +0800 CST

Deleted /boot and removed kernel

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I happen to have deleted the /boot directory on my system instead of on the one I was supposed to.. I found this in order to restore it, however I had problems with apt --reinstall so I decided to remove and install the packages manually. Probably not the brightest idea, now have 2 broken images that I do not know how to fix.

Running dpkg --audit tells me

The following packages are only half configured, probably due to problems
configuring them the first time.  The configuration should be retried using
dpkg --configure <package> or the configure menu option in dselect:
 linux-image-4.15.0-42-generic Signed kernel image generic
 linux-image-4.15.0-43-generic Signed kernel image generic

Running dpkg --configure linux-image-4.15.0-42-generic

Setting up linux-image-4.15.0-42-generic (4.15.0-42.45) ...
Processing triggers for linux-image-4.15.0-42-generic (4.15.0-42.45) ...
/etc/kernel/postinst.d/dkms:
run-parts: failed to exec /etc/kernel/postinst.d/dkms: No such file or directory
run-parts: /etc/kernel/postinst.d/dkms exited with return code 1
dpkg: error processing package linux-image-4.15.0-42-generic (--configure):
 installed linux-image-4.15.0-42-generic package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
 linux-image-4.15.0-42-generic

However /etc/kernel/postinst.d/dkms exists

~$ ls -l /etc/kernel/postinst.d/dkms
-rwxr-xr-x 1 root root 1120 авг 31  2016 /etc/kernel/postinst.d/dkms

My machine is still running though, is it possible to save it?

EDIT:

Just tried to run dkms manually and found out /bin/bash was missing. Installed it with apt install bash and then issued the commands

dpkg --audit
apt install -f
update-grub

Everything looks normal now, however after reboot there is no ubuntu boot option in grub..

boot dpkg kernel apt

1 Answers

    • Boot with a Live Ubuntu Disc

    • Mount the partition/s with Ubuntu file system, on /mnt

    • Example 

      sudo mount /dev/sdxx /mnt
sudo mount /dev/sdxy /mnt/boot
sudo mount /dev/sdxz /mnt/boot/efi

      Where sdx=disk, sdxx="/" partition, sdxy="boot" partition,sdxz="efi" partition

      then run 

      for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done
sudo chroot mnt

    • Most importantly, since you have lost your /boot/grub/efi and may be /boot/grub/efi also.

      • Find your boot type

        [ -d /sys/firmware/efi ] && echo "EFI boot on HDD" || echo "Legacy boot on HDD"

      • If internet problem.

        echo "nameserver 8.8.8.8" >/etc/resolv.conf

        or

        cp /mnt/etc/resolv.conf /etc/resolv.conf

      • For legacy/bios boot

        apt install --reinstall grub-pc grub-common

      • For UEFI(efi) boot

        apt install --reinstall grub-common grub-efi grub-efi-amd64 grub-efi-amd64-bin

      • And

        grub-install /sdx # no apt infront

      • Now run

        dpkg -S /boot
sudo dpkg --audit

    to find the packages needed. Install the packages.

    • Then

      apt --fix-missing install
update-initramfs -u 
update-grub

      and

      exit
for i in /sys /proc /dev/pts /dev; do sudo umount /mnt$i; done

      Unmount mounted partitions.

      Example:

      sudo umount /mnt/boot/efi
sudo umount /mnt/boot
sudo umount /mnt
sudo reboot

    • For errors after rebooting.

      sudo dpkg --configure -a
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