FYI.
sometimes it is necessary to flash the firmware once again 
for me that worked with ‘Amlogic USB Burning Tool’
s.a. [How To] Install run Manjaro ARM on Amlogic TV Boxes with S922X - S905X3 SOC - #81 by spikerguy
You can find the last available firmware for the X96 Air P3 (4GB) box:
X96 Air Amlogic S905x3 8K Video Decode Android 9.0 TV Box Firmware 20201125 - (geekbuying.com)
http://geekbuying.mediafire.com/file/0az4eguf3k0pnif/X96Air_P3_20200831-1753.img/file
may it help if necessary