Note: It is highly likely that "Rkpx3" refers to the Rockchip RK3066 processor, a dual-core chip popular in older Android TV boxes, car head units, and tablets (roughly 2012–2015 era).
As of this article, these are the most stable and feature-complete builds: Rkpx3 Android Update
Android 7.1 (Nougat): Identified by an "N" indicator. Requires a px3.img file. 2. Hardware Preparation Storage: Use a USB thumb drive formatted to FAT32. Note: It is highly likely that "Rkpx3" refers
For most older PX3 units, you’ll need to flash the firmware manually using a file like px3.img or update.img. What You’ll Need: A laptop and a USB thumb drive (formatted to FAT32). Android 13 GSI has been tested on Rkpx3