: Hold INFO and BACK while powering the unit on.
Sometimes a “firmware update” problem is actually a user settings corruption. Before updating, try a : denon avr x4000 firmware update upd
The firmware update had worked its magic, and my Denon AVR X4000 was once again a vital part of my home theater setup. I was grateful for Denon's commitment to supporting their products and for the relatively straightforward update process. : Hold INFO and BACK while powering the unit on
He navigated to the Maintenance menu. The screen warned him: Updating firmware may take up to 30 minutes. Do not power off. denon avr x4000 firmware update upd