Kernel panic - not syncing: VFS: Unable to mount root fs on

I run multiple distro’s on my pc which are of course, periodically updated. Whilst I know this is a previously addressed issue on the forum, is there any way to preclude the Manjaro grub from being replaced by the other distro’s grub upon upgrade?

I have twice got the dreaded Kernel panic now and it’s a pain in the arse to remedy each time – this time after Linux Mint updated I’m finding Manjaro’s grub impossible to reinstate and will have to reinstall Manjaro. I can’t do this each time another distro upgrades.

There can be several ways

  1. chroot from livecd (which you’re aware of, I think)
  2. use this method which does not need chroot or boot livecd but still make manjaro default boot
  3. remove intel-code from manjaro OS but you’ll boot Manjaro without intel microcode enabled
  4. add custom entry to all other OS bootloaders to multiboot to or configfile from manjaro grub.cfg
  5. create manjaro kernel sym-links and add custom entry to other OS bootloader to boot this sym-link
  6. create your own system bootloader and grub.cfg like here
  7. and I think you’re asking for this - set all other OS’s grub to its own partition so that whenever there’s an update in the other OS’s it won’t become default system grub (make majaro grub default first). But remember to update-grub in Manjaro to incorporate new update in other OS new kernel.

sudo grub-install --force /dev/sdax

I followed your tutorial by pressing 'c’
at the Manjaro grub prompt and:

grub> search.file /boot/intel-ucode.img root
grub> configfile /boot/grub/grub.cfg

was able to launch Manjaro.

However, when booted into Manjaro, at terminal,

sudo grub-install /dev/sda
sudo update-grub

did not resolve the issue.

Attempting a further resolution (option #2 on your list) doesn’t work on multi boot disks and is not permitted. Archwiki says:

Warning: GRUB strongly discourages installation to a partition boot sector or a partitionless disk as GRUB Legacy or Syslinux does. This setup is prone to breakage, especially during updates, and is not supported by the Arch developers.

And tells you to use the --force option to allow usage of blocklists.

https://wiki.archlinux.org/index.php/GRUB

Unfortunately this did not resolve the issue.

My grub file looks perfect so I think I’m forced to reinstall but I’ll examine #7 on your list and report back.

Thanks for your help.

sudo grub-install --force /dev/sdax

on Manjaro’s partiton produced:

sudo grub-install --force /dev/sda9
Installing for i386-pc platform.
grub-install: warning: File system `ext2’ doesn’t support embedding.
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
Installation finished. No error reported.

On further reflection, I don’t think there is a satisfactory solution to this “nuisance” problem.

Quickly, 2 things.
o your grub-install /dev/sda
check if you sda is your primary.
Apparently it is not’
If , for example your primary is sdb
then it should be grub-install /dev/sdb

But here, I think you installed to partition instead of device
You’ve used grub-install /dev/sdax
instead of grub-install /dev/sda

Causing the error you’re having.

o Use force for partitions as I shown in my command.
Having done it, it is done, it is working.
Why did you say it didn’t work?

Yes, there is warning. I know. So? It works, didn’t it?

You’re welcome.

No it didn’t work. When rebooted it produced the same condition.

Here’s how I partition my disk together with fdisk output.

I use sda1 to store my data files then make sda2 an extended partition on which I install my distros.

Okay here’s how to do it. (using method 7)
Note: I assume you have 2 different OS’s in sda7 and sda10, namely Ubuntu and Kubuntu.
If they are the same distro, let us know.
If commands have been done, it’s okay to do again.

First boot into Manjaro and at terminal

sudo grub-install /dev/sda
sudo update-grub

Note; it is /dev/sda not /dev/sda9
repeat: it is /dev/sda not /dev/sda9

Then boot into Opensuse, at terminal

sudo grub2-install --force /dev/sda5

note: it is /dev/sda5 not /dev/sda
and for suse (and fedora, mageia…) it is grub2-install, not grub-install

Then boot into Linux Mint, at terminal

sudo grub-install --force /dev/sda6

note: it is /dev/sda6 not /dev/sda

Then boot into kubuntu, at terminal,

sudo grub-install --force /dev/sda10

note: it is /dev/sda10 not /dev/sda

Then boot into Ubuntu, at terminal

sudo grub-install --force /dev/sda7

note: it is /dev/sda7 not /dev/sda

If you install any new OS at installation make grub install to own partition and not to mbr
Remember to update-grub at Manjaro OS after that.

ps: you may want to consider the other methods (1) - (6)
I use method (6) and I don’t have to worry about any grub-update anywhere anytime or when I install new OS.

But since you’re having so much unnecessary problem here, I’d recommend you just uninstall intel-ucode (method 3) in Manjaro. Any OS grub will boot Manjaro okay then.

Success!

I’ve posted the terminal feedback for each Installation. Note the first command failed until I added --force at the end.

Manjaro
grub-install: warning: Attempting to install GRUB to a disk with multiple partition labels. This is not supported yet…
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
grub-install: error: will not proceed with blocklists.

neil@neil-pc ~]$ sudo grub-install /dev/sda --force
Installing for i386-pc platform.
grub-install: warning: Attempting to install GRUB to a disk with multiple partition labels. This is not supported yet…
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
Installation finished. No error reported.

Suse
neil@linux:~> sudo grub2-install --force /dev/sda5
Installing for i386-pc platform.
grub2-install: warning: File system `ext2’ doesn’t support embedding.
grub2-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
Installation finished. No error reported.

Mint
neil@neil-Dimension-8400 ~ $ sudo grub-install --force /dev/sda6
[sudo] password for neil:
Installing for i386-pc platform.
grub-install.real: warning: Filesystem `ext2’ doesn’t support embedding.
grub-install.real: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
Installation finished. No error reported.
neil@neil-Dimension-8400 ~ $

Kubuntu
neil@neil-Dimension-8400:~$ sudo grub-install --force /dev/sda10
[sudo] password for neil:
Installing for i386-pc platform.
kagrub-install: warning: Filesystem `ext2’ doesn’t support embedding.
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
Installation finished. No error reported.
neil@neil-Dimension-8400:~$

Ubuntu
neil@neil-Dimension-8400:~$ sudo grub-install --force /dev/sda7
[sudo] password for neil:
Installing for i386-pc platform.
grub-install: warning: Filesystem `ext2’ doesn’t support embedding.
grub-install: warning: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged…
Installation finished. No error reported.
neil@neil-Dimension-8400:~$

So - whenever a distro upgrades the grub will not affect the other distro’s on my system?

What exactly is the “intel-ucode” and will it be OK to remove it from Manjaro?

Thank you for taking the time to help me with this, I appreciate it.

Correct.[quote=“fastship, post:8, topic:21226”]
What exactly is the “intel-ucode” and will it be OK to remove it from Manjaro?
[/quote]

https://wiki.archlinux.org/index.php/Microcode

Generally, it’s somewhat okay. Some intel processors must have it.
It’s better to have it for others as well but… if it causes too much problem, it’s up to you.[quote=“fastship, post:8, topic:21226”]
Thank you for taking the time to help me with this, I appreciate it.
[/quote]

You’re welcome. Sorry I made a mistake too in the beginning that I assume you’re ‘up to speed’ on grub.
People who are good in linux elsewhere (like you) may not be in grub. Like I may be somewhat okay in grub but bad in other things in linux. Sorry about that.

Oh… one more unrelated thing…[quote=“fastship, post:8, topic:21226”]
Attempting to install GRUB to a disk with multiple partition labels.
[/quote]

Let’s look into this some other time. or another topic.

Cheers, take care.

No, don’t remove the intel ucode! The kernel needs that. You can remove xf86-video-intel if you wish, unless it is an earlier model card.

Regards

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