First try setting the baud rate to
74880. Example for Linux:
python -m serial.tools.miniterm /dev/ttyUSB0 74880
The random symbols should become readable messages.
If you see repeating messages containing
rf_cal !=0x05 then most
probably you should
initialize the flash memory on your ESP8266
To achieve this do the following:
Check the Hardware configuration especially
If you’re not sure what size the flash memory is on your device, run make flashid to check.
cd $SMING_HOME/../samples/Basic_Blink make flashinit
This resets the flash memory to a default state, erasing any existing application, configuration or data stored there.
Re-program your device:
Verify flash data has been written successfully