I have a question. If you already have a9lh and luma installed and you update to 11.3, and you still have your firmware backup from doing the downgrade to install a9lh, can you use your backup to restore your firmware to that version and make it downgradable again, essentially restoring all the previous hacks so you can install them again? For example, for the sake of updating them to work on 11.3... or just to install something that you can't now on 11.3.
Edit: Also to note, when I did it, I believe I also created a full backup along with the quick backup.