Onkyo HT-RC660(B) Service Manual page 24

FIRMWARE UPDATE-2/2
USB Update (service mode)
[Procedure]
Overwriting is also possible.
1. Turn on the unit. It takes some time to start after you switch on the unit.
2. Select the USB input source.
3. Connect the USB storage device to USB port on the unit. Wait until Initializing of USB/NET finishes.
4. Hold down [DISPLAY] button and then press [ON/STANDBY] button twice.
Main version will be displayed, and HYBRID STANDBY indicator will start to flash.
5. Press [RETURN] button. "NET -> ALL_D" will be displayed.
6. Select "USB -> ALL_D" by [PRESET(left/right)] cursors and [TUNING(up/down)] cursors,
then press [ENTER] button, updating will begin.
7. Wait until update is completed. When the update ends, "Completed!" is displayed.
(If you leave it, it automatically turns standby mode. )
8. Press [ON/STANDBY] button, and the unit turns on.
9. Check the new FW version number.
<Note>
If the procedure might not be succesful, please select "USB -> ALL_M".
TX-NR636/ 737/ 838/ HT-RC660/ HT-R993/ DTR-30.6/ 40.6/ 50.6