Luxo
You could also get an Android phone or tablet (has to meet minimum system requirements but doesn't have to be latest and greatest) for your ASIAIR
You can then easily downgrade to whatever firmware you want AND, because you can explicitly say not to update just the ASIAIR App on android, enjoy that firmware for as long as you like.
You could also choose to never update your device OS as well if you want to ensure a completely static and stable astro environment.
I'm still on 2.1-10.74 with my ASIAIR Plus 32GB.
Just a note: unless you really have to - never update the ASIAIR App/Firmware.
Note: with Apple, due to Apple restrictions, you can only turn off auto update for all apps.