Firmware
From Retroid Handhelds
For all current firmware upgrades and guides including stock app restoration packages and root solutions for both 6.0 and 8.1 go to:
https://drive.google.com/drive/folders/1pSDVxLSOLqMirmPENWf2sdxrDKfOLd6z
And remember to please follow the guides closely or it may affect your mood!