Dated reply I know, but for person having that issue having the USB not working.
I have two rs90 and both would not work at all on my dell e7440 laptop windows 10, button combos, cable changes nothing. For the heck of it, i tested on another laptop, dell 6440 (my GFs laptop) with windows 10, same cables and all. Holding A, device popped right up zero issues... both actually. Got the CFW flashed and everything working perfectly.
What i'm saying is its quite possibly not your cable and just your laptop... i'm not sure why at all... all other USB devices work perfectly fine on my laptop.
EDIT: Figured it out... go to device manager... put your USB Hubs OFF power management. Mine worked perfectly after that.
EDIT2: Also noticed if you don't need direct USB access, the 5/17 cfw works faster (more instability) than the 6/1 or the 1/6 cfw. I have all three in my internal memory so i can swap back and forth if need be. All my emus/roms are in my SD card. I'm amazed how well PCE and PCE-CD run on this unit... GBA works amazing as well. Picodrive is close, extremely playable... MegaCD titles are a tad choppy (sonic CD runs about 45-50fps @ 436mhz overclock). Both my units are left at 5/17 fw (regba, picodrive, and temper all seem very stable... apps like doom forget about it... instant crash).
Amazing work for all involved. Unit went from a subpar GBA emulator only to an amazing GBA device... add in full speed PCE (PCE-CD) is amazing... megadrive run well as well. Rest of the emulators I tested didn't run very well (or I'm not too interested in the console/system, although gngeo would be amazing... i think the resolution would be an issue though. That said PCE-CD has fatal fury special and art of fighting which runs amazing.