Hello Rafa,
I don’t think there is a multiplexer inside in FX30 so i don’t think you can use Mangoh’s muxCtrlService.
I am still investigating the issue as it kind of becoming urgent for us.
See at similar other topic:
https://forum.sierrawireless.com/t/fx30-n-reset-iot-pin-mapping-in-legato/9042/1
Let us know if you have already found out new information about the FX30 IOT slot.
Regarding your speed problem:
I use both cfsetospeed() & cfsetispeed() on termios structure or you can also use this new legato API:
legato.io/legato-docs/latest/c_tty.html
Cheers,
tom