Get the 3.2.2 update. Decrypt it with DeBooxUpd.py (Google it). Extract boot.img Flash it.
http://firmware-us.boox.com/fbddd5e0...cbc/update.upx
MD5 = fbddd5e0b6de5d32f2111d6177619cbc
Onyx/NovaAirC/NovaAirC:11/2022-04-23_15-11_3.2.2_559727551f/32979:user/dev-keys