FirmwareMaster blockId issue

[mcallegari]

Hi, this line of code is suspicious:

libartnet/artnet/transmit.c

Line 349 in 61878f9

firm->expected_block %= UINT8_MAX;

It means blockId will never reach 255, but just 254.
I tested the code with a few fixtures and they errored on the 254 -> 0 switch.
Any chance this can be fixed for future versions?
Thanks