If you still see "bootrom error wait for get please check stb uart receive full" after all steps:

: Disconnect and reconnect the power to both the device and the UART adapter. Sometimes other active connections (like a plugged-in USB cable) can interfere with the serial bootloader.

Even if the screen shows this error, the device might still be accessible via a PC connection.

: Sometimes, a simple reboot can resolve transient issues. Power off your device, wait for a few seconds, and then power it back on.