If you continue to get this error after completing these steps, the flash memory chip on your Set-Top Box may be completely corrupted or physically broken, preventing the Boot ROM from triggering its interface. To help pinpoint the problem, could you tell me:
Begin with the physical connection.
Try starting with 115200.
If you provide these details, I can give you the specific and pinout diagram for your device.
Most STBs use 3.3V logic. Ensure your USB-to-TTL adapter is set to 3.3V, not 5V, to avoid damaging the processor. 2. Check Device Manager and Drivers
Bootrom Error Wait For Get Please Check Stb Uart Receive