Four types of hdmi grabber tests (hdmi-cec, rainbow signal) - Hardware Support - Hyperion-Project Forum
Amazon.com: BlueRigger HDMI CEC Less Adapter (4K UHD, ARC, Ethernet, Male to Female CEC Blocker) - Compatible with HDTV, TV Stick, Chromecast, Nintendo Switch, Xbox, PS5, PC, Soundbar : Electronics
Amazon.com: Generic HDMI CEC Blocker Adapter, 4K60Hz/18Gbps, Supports Top Boxes, Apple TV, PS4, Xbox, Blu-ray Players, 1 Year Warranty : Electronics