i was excited to see 9.4.0 show up on my tcl 7138x (aka 75R617) and briefly enjoyed the airplay support. unfortunately anytime i used my tivo bolt, it would continuously blink a black screen and drop audio as if it were trying to acquire a handshake with the hdmi signal. occasionally it would work when initially turned on, but inevitably revert to the intermittent black strobing when changing the channel or bringing up the menu. i tried various hdmi cables, resetting the tivo, resetting the roku, playing with picture settings, forcing auto/1.4/2.0 hdcp and nothing worked.
i have a 4k hdmi switcher which might have been the culprit, but i have an appletv/nintendo switch that was connected through to the tcl that didn't have any issues, so it was only the tivo that was having the issue. however, the tivo worked fine when it was connected through the hdmi switch and directly to a small hdmi monitor so the tivo was working fine otherwise.
i suspected that this started happening recently with the latest update and wondered if i could roll back to an earlier firmware. there's a great thread that describes how to do it:
You may be able to delay it longer before automatically updating: on that same "secret screen" where you rolled back to 9.3.0 is an option to cycle the update server - if its configured for "beta" (not sure with Roku TVs) by default you can change it to "retail" and it will offer fewer updates less often for manual/automatic installation.