system initialization with error: ata2: COMRESET failed (errno=-16)

[trinidad]

You have a couple things going on. The seagate backup disk is GPT because it's 2TB. The installed LL system 300GB onboard drive is DOS. The backup drive is looking for a Windows UEFI entry that isn't there anymore. As far as I know you can't run that backup drive in its current state after installing a Linux OS because it still needs a Windows boot manager. The missing ata initializing file for that drive is gone. Linux will still recognize the drive but it may or may not work for data storage. It is normally not considered Linux compatilbe. I would unplug the backup drive and REMOVE any BIOS entry noting or listing it, then reinstall Linux Lite to the onboard drive without the backup drive plugged in. That should properly designate the Linux drive as sda not sdb. "Possibly" making the backup drive Linux compatible will involve some other steps but that's not worth doing until you get the Linux system installed without the backup drive present.

But... BEFORE you do any of the above see if you can store and then retrieve a Linux file to and from the backup drive. If you can do that you may want to leave it as is. I doubt you will be able to, but it's worth trying. If the data partition is FAT32 and not NTFS it may still work. You may even be able partition a space on it for Linux.

By the way you may still be able to edit the backup drive EFI partition and boot windows from it if there is a full backup on it. (Windows live ent disk should work or even bcedit)
TC