Download Android 7.1.2 stock firmware for Vorke Z6 Plus TV Box from here and 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: VORKE Z6 Plus 20180606
Model: Vorke Z6 Plus TV Box 3GB / 32GB
Image file size: MB
Platform: Amlogic S912
Image: VORKE Z6 Plus 20180606.img
Build number: q201-userdebug 7.1.2 NHG47L 20180606 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.