Hello,
very strange.
My Firestudio-mobile works just fine on my trusty 2008 iMac but when I try to use it with my MBPro from 2013 running MacOS 11.7.11, I get the alternating red / blue
flashing light which I understand, means a synchronisation fault.
I've looked at Universal Control, but there doesn't seem to be anything useful there. A look on the Presonus site indicates that there may be a compatibility issue with MacOS 11.x.x
Both computers are connected by Firewire OUT to USB IN.