I've spent the past two hours trying to tackle the strangest problem.   
I might need to submit a bug report to FTDI or something as it's super 
strange.  When I transmit this exact sequence  "0x04 0x05 0x01 0x0a" on 
linux, on the RX side I get "0x04 0x05 0x01 0x0c".    But it works fine 
under windows.  And it's only that sequence that seems to get tweaked.   
If I change one number by one value, the last digit does not change.  
Super strange.  Took forever to figure out that was the cause of my 
grief.  BTW, this is unrelated to rStep, I just wanted to vent.
Reza.