@koahnig

Not really sure though.... But the problem was solved as soon as I installed Qt Creator from Software Centre, while keeping the libraries for QtSerialPort from .run file downloaded from the website. I really guess that this is about the 64-bit and 32-bit version problem.

Thank you very much for your attention! :D

Regards,
Gen

@Digits
Hi
He has not been online for 2 years so its unlike he return to answer this.
Maybe you can use this
https://github.com/QkThings/qkloader
IT implements XMODEM in a more cpp friendly way using QSerialPort