The RK3228A uses a kernel with selinux=permissive in many stock builds. Pre-rooting involves patching boot.img .
Solder a TTL UART to the PCB’s RX/TX/GND pads (often labeled J1 or J2). Connect to PC (115200 baud) and watch boot errors. This reveals exactly why your repack failed – missing drivers, wrong partition loader, or corrupt DTB. mxq pro 4k rk3228a firmware repack