Setup Menu → General → Firmware → Check for Update
| Firmware Version | Status | Known Issues | |----------------|--------|---------------| | Below 00.60.00 | Unpatched, high risk | HDMI dropouts, shutdowns | | 00.60.12 to 00.65.00 | Partially patched | Occasional sync loss | | | Fully patched | Most stable available | | 00.99.99 (rare) | Service beta | Not recommended |
The Denon AVR-591, introduced over a decade ago, remains a surprisingly capable AV receiver for budget-conscious home theater enthusiasts. With its five channels delivering 75 watts each (375 watts total) and support for Dolby TrueHD and DTS-HD Master Audio, it punches well above its weight class. But like all electronics, especially those from the HDMI 1.4 era, the AVR-591 has its quirks—most notably the intermittent HDMI handshake failures and signal dropouts that have plagued owners for years.
Do not turn on the receiver normally. To accept new firmware files, the internal microprocessor must be forced into its download state. denon avr591 firmware update patched
Once the display flashes, release your fingers from the buttons.
Given the scarcity of official updates, the "patched" update concept takes on new meaning. For the AVR-591, this term usually refers to community-driven efforts rather than an official Denon release.
The most significant fix in the patched firmware involves HDMI handshake reliability. Older firmware versions frequently caused "No Signal" errors, flashing screens, or intermittent audio dropouts when switching inputs. The update optimizes the High-bandwidth Digital Content Protection (HDCP) handshake protocol, ensuring seamless video passthrough from modern devices like Apple TV, Roku, and modern gaming consoles. 2. Audio Decoding and DSP Logic Errors Setup Menu → General → Firmware → Check
For many owners, the best “patch” for the AVR-591 isn’t new firmware at all—it’s upgrading to an external HDMI switcher that handles handshaking more reliably, or embracing the receiver as a dedicated audio processor with video passed through directly to the TV.
Visit Denon’s official support website (support.denon.com) and navigate to the downloads section for the AVR-591. Keep in mind that Denon has marked many legacy products as “end-of-life” and may not host older firmware files indefinitely. Third-party repositories sometimes archive these files, but use them at your own risk.
The AVR-591 supports Dolby TrueHD and DTS-HD Master Audio, but legacy firmware sometimes exhibited Bitstream decoding glitches—pop sounds, momentary dropouts, or incorrect channel mapping during high-bitrate content playback. Patched firmware tightened the audio processing pipeline on the DSP chips, reducing these artifacts. The service manual confirms that firmware updates can affect the Main, Sub, DSP ROM, and Audio PLD components, all of which play roles in audio decoding. Do not turn on the receiver normally
Improves communication with newer 4K TVs, streaming sticks, and modern gaming consoles.
In the world of legacy AV gear, a proper firmware patch can mean the difference between a doorstop and a daily driver. The AVR-591’s patched firmware is a testament to that—a final fix for a well-loved receiver, preserved by a community that refuses to let good hardware die.