Apple Thunderbolt Display not detected using Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter on new Silicon Mac Mini (M1)

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Apple Thunderbolt Display not detected using Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter on new Silicon Mac Mini (M1)

I have a new Mac Mini M1 (Silicon) and an older Apple Thunderbolt display, and I can't get the Mac to recognize the display. I am using the Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter.

Behavior

The Thunderbolt display works fine with my older Intel Mac Mini which has Thunderbolt 2.
When I use the Apple adapter on my new Mac Mini with Thunderbolt 3, the screen is totally black.
If I connect a second monitor to the new Mac via HDMI, the HDMI display works, the Thunderbolt does not.
The USB C ports are working fine with other devices.
When using the HDMI display and connecting the Thunderbolt display as a second monitor, it does not show up in the display settings or system report; it's totally undetected.

Compatibility - Apple says the Mac Mini is compatible with the display in this article. The page above for the adapter also lists the "Mac mini (M1, 2020)" as a compatible device.
Firmware - The Apple store recommended I upgrade the firmware on my Thunderbolt display, but when I got home, I found it was already at the latest version.
Adapter and Testing- I brought my adapter and new Mac into the Apple store, and everything worked fine with a different Thunderbolt display that had in the store. They also swapped out my adapter for me to try a new one at home, but there was no change in behavior.

Does anybody have any further recommendations or things to try? Has this happened to anyone else? It seems like my specific Thunderbolt display is the culprit, but I can't figure out why it works fine on my old Intel/Thunderbolt 2 Mac Mini, but somehow is non-functional with the new Silicon Mac Mini with Thunderbolt 3. The person at the apple store said that he's heard about this issue but because it's so new, they didn't have any details to share.

Thanks-

Joel

Mac mini, macOS 11.0

Posted on Dec 7, 2020 11:00 AM

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Answer 1

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joelasil Author

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24 points

Dec 14, 2020 3:18 PM in response to joelasil

UPDATE 12/14/20 - My Thunderbolt display did not work with one of the new M1 laptops in the apple store (can't recall the exact model); however the same laptop did work with a different Thunderbolt display the apple store had in their graveyard.

It seems that this is a problem with my specific display, and not "all thunderbolt displays". The display works with various Thunderbolt 2 devices, but no Thunderbolt 3 devices (while using the adapter). It still sounds strange to me, because the signal coming out of that adapter "should" be a regular Thunderbolt 2 signal; I can't think how it would be any different.

The apple store has my display and is going to attempt to re-flash the firmware, and I'm waiting to hear back. Somebody from apples outreach team has also contacted me (Patricia).

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Answer 2

Dec 7, 2020 12:46 PM in response to joelasil

Something seems odd. While I don't have the Mini, I do have one

of the new MacBook Airs (8 cpu/8 gpu). It is basically the same

hardware with two Thunderbolt 4 ports. On my machine, with the

same window you are showing, I have 2 Thunderbolt busses displayed

and my Thunderbolt display is working just fine ( I have seen the Mini and

the MBA teardown and both have two TB controllers):

Also, I don't see a Cable Firmware Version listed on yours.

You also have two link status values listed. Not sure what that means.

Also I note the route string is different. What it means, if anything, I

don't know as well.

Out of curiosity, if you have an extra TB cable, connect it to the

open port on the TB display and then connect it to your Mini

with the adapter.

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Answer 3

joelasil Author

Level 1

24 points

Dec 14, 2020 3:20 PM in response to woodmeister50

Thanks for the reply. That screenshot was from my 8? year old Intel mac mini, so things have likely change a lot. I couldn't get that info from the new M1 mac mini because the display is totally undetected. I just posted an update if you were curious about following along. However, the apple store has my display and is trying to re-flash firmware, so hopefully that will take care of it. Thanks again.

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Apple Thunderbolt Display not detected using Apple Thunderbolt 3 (USB-C) to Thunderbolt 2 Adapter on new Silicon Mac Mini (M1)

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