[SOLVED] Blank Screen a few hours after Updating to 21.1

[avalon20]

Hi.

Earlier today I decided to upgrade my Linux Mint Cinnamon from 20.2 to 21.1.

I have a couple of HDDs, an SSD and an NVMe drive.

My NVMe looked like this:

EFI 300 MB
root (Mint 20.2) 224 GB
/home 595 GB
Swap 6GB
Unallocated 155 GB.

I decided to install 21.1 into the Unallocated chunk at the end.
I took backups of my app configs using the Mint Backup tool, along with backups of my /home partition. These were taken to an external HDD.

I created a bootable USB and fired it up in my PC.

During install, I elected for "Something else".

I installed 21.2 into the "unallocated" piece as a new partition and didn't reformat any other partitions.
The installation appeared to go fine and I rebooted, having removed the USB thumb drive.

When it booted up, I restored my apps from the backup.
I then renamed the home folder and modified the /etc/fstab file to include the original home partition.
I also added in a couple of partitions which were on HDD.

I rebooted and magically, when I logged in, things looked very much like my 20.2 desktop (even my Conky display was up there!).
I spent most of the day using it and even rebooted a couple of times. I was occasionally flipping to other machines via KVM switch. At one point I switched back to my upgraded machine and the screen was blank. I eventually powered it down and tried to reboot. The grub menu appeared, but when I tried to start any of the Linux Mint options it wouldn't boot - there seems to be activity (drive light flashing) but a blank screen. I then tried booting from the thumb drive and that behaved in the same way - after the grub menu choice, I just got a blank screen. I tried the thumb drive in another PC and it booted fine. I also have Oracle Linux on the machine (installed on a HDD) and that boots in a VGA mode.

I am finding that I can boot the thumb drive in in compatibility mode, and I tried to install 21.1 to the SSD, which installed ok, but I just couldn't boot the OS once done.

I can boot in recovery mode from the grub menu and dropping to root, I can do a

Code: Select all

df

and see all my filesystems.

To summarise,

• I can boot from the thumb drive in compatibility mode;

• I can boot recovery mode;

• I can boot Oracle Linux in VGA

• Cannot boot in regular mode from the thumb drive or from my PC.

I'm not sure what else to try. I am wondering whether this is a massive coincidence and I have hit an obscure hardware issue a few hours after the upgrade.

Any suggestions appreciated.

Thanks,

Clive

[hal8000]

There may be two things that caused this to break:
1 KVM switch
2 Your Restored backup.


If you can get into recovery mode, can you log into your new Mint 21.1 ?
If you can you can try

sudo apt update
sudo apt upgrade

Not forced to work but may renew or overwrite any configuration files that have corrupted.

If you cannot rescue your system, you may be looking at re-installing (as its a fresh install and you have backup, there wont be much to lose).

If you do have to reinstall,
You only have to allocate about 30G for the / partition. My previous system allocated about 25G and never used more than about 70%.

If you do re-install, do not restore your backup immediately.
Use LM for an hour or so, reboot, shut down completely, restart.

Do this a few times then you can be certain that all is ok.

Then try reinstalling your backup.


You have to be extremely careful with backups, it can be like installing a time bomb.
Depending on what was backup up and what you're restoring can overwrite critical
system files.
You did say your old System was Mint 20.2, so without going through a changlog, you
would need to know what has changed and what was restored.

If all works without problems, your system is cured, if you return to non-booting and a blank
screen, I would guess your backup has restored an older kernel, an older partition table, or
something else critical to operation.

It is however safe to backup your saved data from your home partition and files youve worked on.

[avalon20]

Hi and thanks for the suggestions.

I actually took it in to a local PC specialist. They reported that it worked fine!

Although I doubted it was the issue, due to my experimentation, they suggested taking the KVM out of the equation, and trying a direct connection to the monitor. Remember, I had a number or PC's connected and working fine via the KVM, all using the one monitor.

Anyway, when I started sorting the cabling, I moved the monitor, and the HDMI cable dropped out! It had been hanging by a thread.
When I re-seated the cable, everything was fine. So the bottom line is, that the one PC was more sensitive to the loose cable than the other 3 PC's.