HDMI Control / CEC with 4K Genie Mini and Samsung TVs

Just got two Samsung Q7DR TVs (2019 model) from Costco and am having difficulty setting up CEC / HDMI Control / Anynet+ with 4K Genie Minis. Clients are the C64K-700, client version is 0x12c5, Genie is the HR54/500 version 0x12e5. Samsung software version is 1351. On the 4K Genie Mini, HDMI Control is on in Settings > Display > Video. On the Samsung TVs, Anynet+ (HDMI-CEC) is “green” in Settings > General > External Device Manager. Cables are verified to be compatible with CEC by using them with other devices on the Samsung TVs. The 4K Genie Mini is connected directly to the TV, not through a receiver.

A PlayStation 3 and a Blu-ray player are immediately recognized by the Samsung TVs when plugged into any of the HDMI ports. The TV will show the name of the connected device and pass commands through to the device from the Samsung remote.

When the 4K Genie Mini is connected to the TV, a wheel spins on the Samsung screen with the message “Detecting device…” Eventually, an HDMI icon with the word “Unknown” shows up along with the message “Device is not detected”, prompting for manual setup. In manual setup, “DirecTV Digital” is chosen (not U-verse). At the end of manual setup, a “DirecTV Authentication“ screen comes up, requiring a selection of “Genie Box 1” or “Genie Mini / Other Box”. I have tried both without success. I have tried this on all of the HDMI ports on the Samsung TVs. At the end of the process, sometimes I get a message from the 4K Genie Mini that it is completing RF remote setup, and I’m prompted to hold mute and enter on the DTV remote. No idea why this happens on some occasions and not on others.

The event logs on the Samsung at Settings > Support > About This TV show multiple entries with “CEC Command,Source enabled”.

5+ minute power disconnects (on both devices), 4K Genie Mini red button resets, and using Settings > General > Reset on the Samsung TVs (without a restore from the Samsung account) do not fix the issue. Without success, I’ve also tried the steps at this link (although they must be slightly varied because of the later Samsung model being used): https://forums.att.com/conversations/directv-dvr-receivers/my-fix-for-genie-minis-samsung-4k-tv-black-screen-resets-resolution-changes/5deff889bad5f2f606a2ac8d.

I had a 4K Genie Mini that had never been used, and I went through the swap / replace process with the Genie to try it out. It was immediately recognized by the Samsung TV, and commands were passed from the Samsung TV remote to the DirecTV. After power cycling the 4K Genie Mini, it no longer worked and I was back where I started.

Samsung Support (800-SAMSUNG) suggests that the 4K Genie Mini is at fault, and I hung up with DirecTV support after switching in the new 4K Genie Mini, but before I power cycled it. My general feel was that DirecTV support had no idea what was going on.

The setup works fine with a 2016 KS9000 and a 4K Genie Mini.

Any thoughts or experience on getting this resolved? Thanks.