Download Android 9 stock firmware for HK1 Plus 2GB RAM TV Box from here or here. Download Android Oreo 8.1 stock firmware for HK1 Plus 4GB RAM TV Box 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: HK1 PLUS 2G S905X2 9.0 25.05.2019
Image: HK1 PLUS 2G S905X2 9.0 25.05.2019.img
Archive file size: 1.03 GB
Model: HK1 Plus TV Box 2GB RAM
Platform: AMLogic S905x2
System: Android version 9
Build number: franklin-user 9 PI 20190525 release-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.