Update in wrong tab - mixing Core and Scale.

[Crumar]

So, I have done it. I messed up my main system.
Situation before:
2x TrueNas 12.0-U1.1 running:
A = Main
B = Backup (Replica of A)

Steps I did:

1. Reinstall B with Truenas Scale 20.12
2. Replicate Storage from A to B again
3. Ensure that I can access data on B
4. Test something with docker on Scale
5. Doesnt work, so I think "lets switch to nightly Scale"

Now at item 5, I was a bit distracted and picked up the wrong tab. I uploaded the update file to system A instead of B.

So, my main system A (formerly TrueNas 12.0-U1.1) is now booting Scale... I am able to login, and I can see the boot environments as well.
I was really suprised to get that far, but nonetheless. I select TrueNas as Reboot, but it always boots scale. I suspect the boot files have been overwritten?
Is there a possibility to remove Scale and get back? Or do I have to reinstall TrueNas from Scratch?

Thanks for all possible advice.
And yes, I know I screwed up.

 

[Samuel Tai]

You'll probably have to reinstall. I believe TrueNAS uses the FreeBSD BTX bootloader and Scale uses GRUB, so you've overwritten your boot sector with a new bootloader that didn't know about any of the old boot environments.

 

[Crumar]

Well, I guess a check of the file blocking / reminding the stupid user would be a good idea.

At least reinstall brought my jails and VM back almost instantly. Now to the rest of the configuration :/.

(I have installed on a new SSD, so if anyone has a hint to get the old working, I will still take it)