Thunderbolt Display flickering with new MacbookPro M4

Are you using the Thunderbolt Display's built-in "hydra cable"?

Recent versions of macOS are reportedly picky about display transmission errors – as in, they don't want to see any, and will cut resolution or signal if they do. Disconnects might suggest a built-in cable which was "good enough" for an older version of macOS (that didn't call attention to the errors), but not good enough for Sequoia.

A workaround for that is reportedly to run a Thunderbolt 1/2 cable from the TB2 side of the TB3-to-2 adapter to the Thunderbolt daisy-chaining port on the Thunderbolt Display – leaving the flaky cable unused. Thunderbolt 2 cables have the same connectors as Mini DisplayPort ones, but back in the day, were built to higher standards. A problem with this workaround is that given how long it's been since Intel moved Thunderbolt to the USB-C connector, one of the old-style Thunderbolt cables may be hard to find.

Caveat: I don't know if the flickering and light and dark bands might just be due to a flaky hydra cable, or if they might be an indication of some more serious hardware failures starting to happen to that old Thunderbolt Display.

fish_tattoo wrote:

Same issue on a closed post:

External monitor flickering with new MacbookPro M4

External monitor flickering with new Macb… - Apple Community

My Apple Thunderbolt Display flickers with light and dark bands when connected to my new Apple MacBook Pro M4. The M4 (48GB/2TB) is connected to the display with the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter. The flickering stops when I switch back to my Apple Mac Mini (Intel). I have also tried the other USB-C ports on the M4, but the display still flickers. The display will also disconnect and turn black. When this happens, the display is no longer listed in Settings > Display. The flickering and disconnect is not constant, but consistent enough to be unusable.

"Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 adapter"....?

current Thunderbolt 5 for the M4