PRO MOD:
1 Disconnect ethernet, and any USB devices, and power up the player with no disc in the tray.
2 Press "setup" on remote
3 Scroll down to "Device setup"
4 Place the bar on "Firmware Upgrade"
5 Press RED-8-5-2-0 on the remote.
6 In this menu, press 1-1-4 on the remote.
7 Exit menu again by pressing setup button, NOT the ok button.
8 Now you can downgrade the firmware with the use of a usb stick, just follow the usual instructions from Oppo.