I followed qnap guide and moved the 2 disks in the TS669L having only the two disks. It does not even show the web interface. I will need to find a way to restore from the backup to the same NAS
The two HDD from the TS-210 also if put back in the original nas do not work anymore, at the start the QNAP is asking to upload a firmware image.
Is there a way to put at least one of the two in the TS669L to access the content?
what would be the advice? format both drives create a new raid 1 for the two disks and restore the data with HBS3 from the backup HDD (another local volume on the same NAS?)
Are you willing to listen to advice or just do your own thing and then complain about it after?
Putting drives in a different QNAP executes a migration, of course they will not work anymore in your ancient NAS. If you have backups(two people told you to have them before doing anything) then why are you trying to move these disks? Kill the disks completely (e.g. diskpart with clean option) or get some new disks and use them instead