The RAMBO board uses the same version of Repetier Firmware for all computing platforms (PC, MAC, LINUX, etc) but there are some things that may need to be changed for host software such as MatterControl running on MAC & Linux based computers.
The Baud Rate will need to be updated in the firmware and in the MatterControl software to be 115200.
I can't find an article talking about how to update the firmware. I've updated arduino boards before, but not sure about Rambo boards. Are there instructions?