Try installing PocketSnes .app and/or SNES.Sim Again and then update the jukebox...
I have the older Dingoos and with all mine, i plug into usb the Dingoo goes into USB Mode, PC detects a Mass Storage Device (or 2 if SD Card inserted in Dingoo).
When ever i add or remove or move and files on the Dingoos and i unplug the USB the Dingoos automatically update the jukebox.... so i have never had to Manually do this, maybe you never had to with the older Dingoo A320s
The Serials on mine was 4G 320WH (or BK for Black Dingoo) followed by 7 digit number.
Right now i'm using the PocketSnes.app and i've already updated jukebox and it didn't fix the sound. So now I'll remove it, unplug my dingoo, plug it back up, and then add it on again and see if that helps.
Is there anyway to fix the dingoo from freezing in usb mode though? Everytime I plug it in to put files on I have to reset it.
Also one more question, is there anyway to transfer save files from the gnuboy.sim to the ohboy.app? I played about 30 minutes of a gameboy game on gnuboy before I got the ohboy to work, and it won't recognize the gnuboy save file.
Thanks in advance.