Hi Michael,
Just an insight on why Legato is not running properly on your AR7556. As you mentioned in your other thread, the AR7556 is designed for China without integrated audio codec. There is at the moment a dependency between the audioService and the modemService (for voice call). I suspect that because there are no audio codec on your module, the audioService cannot initialize properly; hence, all modem services such as sms, data etc… does not work either.
By the way, how did you get an AR7556?
Thank you,
Enoch