I have recently purchased the StellarmateOS (mainly for the companion app) and I am unable to get the SynScan driver to communicate with my mount.
I have a very basic Skywatcher (skywatcher.com/product/az-gt/) with a v4 HC and the latest firmware.
It does work with a PC (no issues using it with stellarium native, or ASCOM).
I AM able to connect to it if I tell Stellermate that its a NexStar (although its a bit iffy, there seems to random problems when doing an alignment) and I can also connect if I say its an EQMod (although it will connect, I doubt it will be usable as EQmod doesn't have an Az mode).
I have tried all the different baud rates, PC Direct mode on and off, as well as the legacy SynScan drivers and am still unable to get a connection.