Installing Android 7.1.2 (NHG47K) on an RK3229 (RK322XBOX) TV box requires flashing firmware via a Windows PC using the Rockchip Android Tool and appropriate USB drivers. The process involves putting the device into loader mode by holding the reset button while connecting the USB-A to USB-A cable. For detailed, step-by-step flashing instructions, see the guide from Firmware Upgrade Guide for Rockchip Devices - Ugoos
Prepare a USB Drive: You'll typically need a USB drive formatted to FAT32. The size requirements can vary, but 8GB or more is usually sufficient.
⚠️ Important warnings:
Flashing a new ROM involves putting the device into "Maskrom" or "Loader" mode to allow the PC to rewrite the internal storage. Generic RK322X (rockchip-rk322x) - postmarketOS Wiki
3.3 Tool Configuration
While holding the button, plug the USB cable into the box's OTG port (usually USB-4 or the port closest to the SD slot) and the other end into your PC.
Once the tool says "Found One LOADER Device", release the button. android rk322xbox rk322xbox 712 nhg47k install
Upgrade: This tries to keep your data (Not recommended for fixing boots loops). Click Restore.