I would guess they have one fixed firmware - which you can't upgrade. But the only place I'd use a hot firmware swap would be between a + quad and an x quad.
Changing between flight modes can be achieved by simply toggling one of the four DIP switches, no PC interface needed!
I received my i86L yesterday, and this thing seems super simple! I only glanced at the manual, strapped it to my 350mm quad, did the quick calibrations for Stick Center, ESC Throttle Range (again with the flip of a couple of switches), and without adjustments to any of the three gain POTs it flew like a dream.
I was able to flip, roll, and loop right out of the gate, so the acrobatic potential for this thing after some fine tuning of the Gyros, should suit
my needs just fine.