: Download your tablet's exact matching Alldocube Stock Firmware Package . You will need the vbmeta.img file from this package to bypass Android Verified Boot (AVB). Step-by-Step Installation Guide Step 1: Unlock the Bootloader

) and your (maximum battery life vs. latest Android version), I can narrow down the best ROM for your needs. Share public link

(Must be reapplied after reboot unless scripted.)

fastboot oem unlock

Before embarking on the custom ROM installation journey, it's crucial to prepare your Alldocube iPlay 40:

fastboot flashing lock