it doesnt play WAV..I tried it... its a joke because it wouldnt take much for Oppo to work up the files that are needed to play flac and wav and make them available. It would be a good hack for someone to figure it out and make it available.
I use the USB inputs on my UDP-205, BDP-105, and BDP-95 to play hi-res FLAC files, and WAV files. (Players listed in reverse chronology.)
(I do not own the earlier BDP-83, and don’t know what types of files it supports from its USB port.)
I use a DV-980H (older than all Oppo models listed above) for playing SACD and CD in my office system. I had never tried playing music from the USB drive on my DV-980H. (In my office I use my PC for playing FLAC and WAV music files.)
I just did a brief test of my DV-980H, and was able to play an MP3 file from a USB drive, but not WAV. (Apparently I was wrong in my post above about WAV.)
IMO Oppo does a good job of providing firmware updates to its recent products, sometimes delivering new features at no additional charge. My understanding is that the DV-980H is 4 generations old. (More than 10 years old.) Every manufacturer must draw a line on updating old products.
IME the DV-980 works good as an SACD/CD player. It seems to me that if you want more advanced features than what the DV-980H provides, you need to buy a newer product. (I don't know anything about hacking old products.)