Using an arduino uno I can change the text 1 time by sending t0.txt="12345"0xff,0xff,0xff. When I attempt to send a new string to t0.txt later using the same format it will not work. Any ideas what is going wrong.
post HMI file and source code
The Iteadlib Arduino Nextion Library is open source and do as you will style licencing.
It can certainly be used as a reference and guideline