Patched | Denon Avr591 Firmware Update

Sudden loss of sound when decoding Dolby TrueHD or DTS-HD Master Audio streams.

This is the most effective "soft fix." Turn off the power. Hold SOURCE DIRECT and INPUT MODE buttons.

It cannot connect to the internet for "Over-the-Air" (OTA) updates.

To determine if your Denon AVR-591 actually requires a patched update, you can access the service menu to read the current microcode version: Turn off the receiver. denon avr591 firmware update patched

Step-by-Step Guide to Executing the Microprocessor Initialization

If you are experiencing issues and cannot find a firmware file, Denon recommends several hardware-based resets:

Which are you running on your computer?

If an input suddenly loses audio, the internal HDMI handshake latch has likely frozen.

As of April 2026, Denon no longer actively releases new firmware for 2010-era models like the

This article explains the firmware patch, the problems it fixes, and how to update your receiver. Key Takeaways Sudden loss of sound when decoding Dolby TrueHD

If a factory reset does not solve your issues, the problem likely stems from modern format mismatches rather than corrupted firmware. Use these patched workarounds to keep your AVR-591 running flawlessly with modern gear: 1. The 4K / HDR Video Bypass

(now rarely available) through a RS-232 service port, which most home users cannot easily access.

Unplug all HDMI, optical, and speaker cables to prevent signal interference. It cannot connect to the internet for "Over-the-Air"

Unplug the power cable of both the TV and the AVR-591 from the wall outlet for 5 full minutes. Plug the TV back in first, turn it on, and then plug in and power on the Denon. This forces a clean hardware handshake reset.

: Denon has largely stopped providing firmware downloads for legacy units. They generally recommend contacting an Authorized Service Facility for updates on pre-HEOS models.