Download Android Pie 9.0 firmware for X88 Pro X3 TV Box from here or here. Download previous firmware from here. Download Amlogic USB Burning Tool v2.1.6 from here or download Amlogic Burn_Card_Maker v2.0.2 from here.
Archive name: x88pro-s905x3_d4_sp6255_x88prox3_20200425_r1
Archive file size: 779 MB
Model: X88 Pro X3 TV Box
Platform: AMLogic S905x3
System: Android version 9.0
Build number: franklin-userdebug 9 PPR1.180610.011 20200425 test-keys
Caution Please do not update firmware unless you know what you are doing, you really want it or it is absolutely necessary. Firmware updates may occasionally have bad results, like bricking your device, temporarily or permanently. The firmware update process is done entirely at your own risk. Before attempting to update the firmware, back up your data.