HDMI 2.1 bug fixed on Denon and Marantz AV receivers released after May 2021

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Buyers of Denon and Marantz AV receivers released after May 2021 are promised normal HDMI 2.1 connectivity without additional manipulation.

As a reminder, as soon as global manufacturers released their first AV-receivers with HDMI 2.1 support at the end of 2020, it turned out that they used defective chipsets that impeded the operation of this interface.

Since then, they have taken various measures to eliminate this problem, including the recall of devices.

Finally, according to Forbes, Sound United, which owns the brands Denon and Marantz, announced that AV receivers and amplifiers released after May 2021 are equipped with new HDMI 2.1 chipsets with normal functionality. That is, the bug that did not allow the transmission of 4K / 120Hz and 8K signals to compatible TVs has been fixed for the following models:


  • AVR-A110 / AVC-A110
  • AVR-X6700H / AVC-X6700H
  • ARV-X4700H
  • AVR-X3700H / AVC-X3700H
  • AVR-X2700H / AVR-X2700H DAB
  • AVR-S960H


  • AV7706
  • SR8015
  • SR7015
  • SR6015
  • SR5015 / SR5015 DAB
  • NR1711

For those who bought these devices earlier, Sound United offered a  solution  in April of this year, which was to use the free SPK618 adapter and update the software.

Denon AVC-X4700H

Well, for those who are just going to purchase a brand new device from the list above, the question arises, is the selected copy defective? For this case, Sound United gives a hint that models with normal HDMI 2.1 function have serial numbers from  ******* 70001 and up.