Ok I'm stuck.
So I enter in the last 63 digits of the serial number but I changed the last letter from e to f:
There are definitely more than 63 digits in the current serial number (see previous attached image), so thats partly why Im confused . . .
Anyway, I push 'Program Device', a short 3 second wait occurs, then it stops. No errors or messages or anything. The serial number hasn't changed. A hardware reset doesn't change it either.
The instructions say:
When the serial number of a CP210x device is changed and the device is reset by calling the Host API function CP210x_Reset(), the device will re-enumerate and the device driver will be installed.
The 'CP210x_Reset()' is in the source code header file, so I am assuming its automatic with the program.