Nothing is removed (almost nothing - in file browser I've removed only jpeg preview, to display more chars in filenames). The problem is that 1.09 firmware has sometimes problems with ogg files. As I heard, in 1.20 firmware this bug has been removed, but I'm not using ogg files, so I don't know if it's true. But you can install modded 1.09 firmware and check if it will handle ogg files. If no, you can install some other firmware.
BTW. Original firmwares you can download from "Download" section on this page (check buttons on top of page). There is also original and other modded firmwares on:
http://www.pioneerfaq.inf...stion=Firmwares