Mr. Innundo has posted a new media compatibility list for GSA-4120B and GSA-5120D. Both with official A102 firmware.
All tests were done in GSA-5120D. He’s one of the first users of GSA-4120B and also one of the first users of GSA-5120D.
GSA-5120D has no problem writing at 12x using USB 2.0 port.