Download latest Android KitKat 4.4.4 stock firmware for Onda V820w tablet from here or here. Download another Onda firmware from here.
Archive: V820w Android OSFirmware: Android KitKat 4.4.4Image file name: V820w 双系统_Android OS固件Model: Onda V820w tablet
Image file size: 534 MB
Platform: Intel Bay Trail Z3735F
Build number: inet_w-userdebug 4.4.4 KTU84P eng.inet_rance.20150113.151126 dev-keys