Then began the "Long Stare." A progress bar made of tiny digital blocks began its slow crawl across the VFD display.
If you tell me the displayed in your "Firmware Information" menu, I can help you determine if you are already on the latest release. Firmware AVR-X520BT Denon Avr-x520bt Firmware Update
Press the button on your remote control to open the on-screen menu. Navigate to General > Firmware > Update Start . Then began the "Long Stare
Never, ever use a firmware file from a third-party forum or random blog. Only use the official Denon website. A fake firmware file can permanently destroy your receiver. Denon Avr-x520bt Firmware Update