develone wrote:Let me if this makes sense, that the long write time was hanging it up?.
Maybe, looking at the code in checksum_ultibo.c it does fopen() and then fputc() for every character so it certainly won't be fast.
It still shouldn't stop it from working, it would just be quite slow. You might be better to use something like fputs() to write the complete string at once.
We can do some tests with your project and a large gps.dat see what results we get.