Press and hold the (usually hidden inside the AV port).
To install the firmware, you will need a Windows PC and a . rk322x-box firmware 8.1 download
This is a Russian forum that is effectively the world headquarters for TV box modding. You may need a browser translator, but their RK322x threads are the most comprehensive. Press and hold the (usually hidden inside the AV port)
Flashing custom/stock firmware may void your warranty and carries a risk of bricking your device. You assume full responsibility. Backup your original firmware before proceeding. rk322x-box firmware 8.1 download
Always download firmware matching your specific Wi-Fi chip configuration to ensure wireless connectivity works post-flash.
Try changing the USB port on your PC. Always prefer rear motherboard USB 2.0 connection slots over front-facing USB 3.0 blue slots.