The first generation of Yamaha's HDMI 2.1 receivers are defective. The company has announced that it will replace the HDMI 2.1 board in the affected products.
The HDMI 2.1 sagaSound United, the company behind Denon and Marantz, has seemingly given up trying to fix the HDMI 2.1 issues in its receivers, offering an external adapter. Yamaha on the other hand will replace the HDMI board in the RX-A2A, RX-V6A, and RX-V4A receivers. - "A free update program will be available starting in fall 2021 to update the HDMI board on these AV receivers to allow for the 4K/120Hz signal transmission," the company announced. Yamaha said that the HDMI board upgrade is complimentary for 24 months after the program starts. It will provide an update on the next steps "this summer". The company also said that the new HDMI board is only required if you are "planning to connect an Xbox Series X gaming or a NVIDIA RTX30 video graphic card device at 4K/120Hz signal transmission" but you should ignore that advice. The issue is not related to these devices but rather the HDMI 2.1 board in the receiver. The Yamaha receivers will most likely also cause trouble with future HDMI 2.1 players and consoles. Yamaha added that its second generation HDMI 2.1 receivers are unaffected by the HDMI 2.1 issue, although they will still require a firmware update to enable the functionality. - "The newly released RX-A4A, RX-A6A and RX-A8A are unaffected by the pass-through issue, requiring only a future firmware update to enable certain HDMI 2.1 capabilities." - Source: Yamaha