Download Android 7.1 stock firmware PC version for MXQ PRO 4K TV Box from here. Download Android 7.1 stock firmware SD card version for MXQ PRO 4K TV Box from here. Download previous firmware from here. Download Amlogic USB Burning Tool v2.0.8 from here or download Amlogic Burn_Card_Maker v2.0.2 from here.
Archive: MXQPRO_S905W_20171218 / MXQPRO_S905W_20171218_SD
Model: MXQ PRO 4K TV Box
Image file size: 817 MB / 826 MB
Platform: Amlogic S905W
Image: aml_upgrade_package.img / mxqpro-ota-root.zip
Inside archive: firmware + factory_update_param.aml + recovery.img
Build number: Amlogic/mxqpro/mxqpro:7.1.2/NHG47L/root:userdebug/test-keys / mxqpro-userdebug 7.1.2 NHG47L root 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.