So I thought I had faced the typical problem of getting a superblock corrupted (which I think happened because of an intended hard/unclean reboot). However after following the guide in the first accepted answer of the linked question, by restoring an alternate superblock, the system is still booting into (initramfs). [NOTE: after using fsck like advised in that answer, I could successfully mount the filesystem and copy stuff from it, and create a folder inside it with sudo rights.]
At the beginning, I didn't get any text before the (initramfs) prompt, except for:
BusyBox v.1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash)
Enter 'help' for a list of build-in commands.
But now I sometimes get also this:
Gave up waiting for root device. Common problems:
- Boot args (cat /proc/cmdline)
- Check rootdelay= (did the system wait long enough?)
- Check root= (did the system wait for the right device?)
- Missing modules (cat /proc/modules; ls /dev)
ALTER! /dev/mapper/ubuntu--vg-root does not exist. Dropping to a shell!
So then, given that restoring the superblock didn't work, what options do I have to fix my boot? I imagine I could try to reinstall Ubuntu from LiveCD/LiveUSB but I have to add an aspect which adds extra complexity: my main hard disk partition is encrypted (by using the default Ubuntu way, which I guess is called LUKS).
Is there a way to fix the boot without reinstalling? Or reinstalling without wiping everything? Should I debug my problem by looking at the boot logs? (If yes, where are they?)
Booting from a LIVE ubuntu USB ISO, I can issue a fdisk -l /dev/sda command, and the result is:
Disk /dev/sda: 447.1 GiB, 480103981056 bytes, 937703088 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x60229a0a
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 999423 997376 487M 83 Linux
/dev/sda2 1001470 937701375 936699906 446.7G 5 Extended
/dev/sda5 1001472 937701375 936699904 446.7G 83 Linux
And this is the result for sudo blkid -c /dev/null:
/dev/loop0: TYPE="squashfs"
/dev/sda1: UUID="7ec61194-f216-4f1b-b684-5b2e2d643c25" TYPE="ext2" PARTUUID="60229a0a-01"
/dev/sda5: UUID="11613ca4-65f2-4079-a750-6f71b6318903" TYPE="crypto_LUKS" PARTUUID="60229a0a-05"
/dev/sdb: UUID="674B-9411" TYPE="vfat"
FWIW, if I mount my encrypted drive via nautilus, I can open /etc/fstab in an editor, and these are the contents:
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
/dev/mapper/ubuntu--vg-root / ext4 errors=remount-ro 0 1
# /boot was on /dev/sda1 during installation
UUID=7ec61194-f216-4f1b-b684-5b2e2d643c25 /boot ext2 defaults 0 2
/dev/mapper/ubuntu--vg-swap_1 none swap sw 0 0
UPDATE: If I press shift at grub booting time, then I can see some options before it goes to boot into (initramfs):
- Ubuntu
- Advanced options for Ubuntu
- Memory test (memtest86+)
- Memory test (memtest86+, serial console 115200)
If I choose the first, then I get the (initramfs) boot. If I choose the second, then more options show up:
- Ubuntu, with Linux 4.4.0-28-generic
- Ubuntu, with Linux 4.4.0-28-generic (upstart)
- Ubuntu, with Linux 4.4.0-28-generic (recovery mode)
- Ubuntu, with Linux 4.4.0-24-generic
- Ubuntu, with Linux 4.4.0-24-generic (upstart)
- Ubuntu, with Linux 4.4.0-24-generic (recovery mode)
If I choose 1 here, the result is the (initramfs) prompt as well.
But if I choose the option (4), the computer asks me for the encryption password and boots alright!! So then, I guess the kernel 4.4.0-28 is at fault here, how to get rid of it and mark the -24 as default?
