I have 2 airtel boxes first is updates disabled usb debugging try 10 times remove power cable trick but not working won't downgraded
And another one is old version patch level 2019 and i successfully converted it to fully android box
So what I do with it
First must enable usb debugging and open yr phone hotspot but do not turn on internet otherwise yr box will be updates to latest version after that connect yr box wifi with yr phone and connect it with remote adb shell app via ip address and remove this
com.airtel.tv
com.firmware.update
com.technicolor.checkota
com.uei.uas.airtel
com.apps.updater
com.tataelxsi.icx
com.technicolor.enableUpdates
After success install atv launcher with es file explore app
And someone who actually downgraded his airtel box please reply