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OUM2303279 Author

Level 1

29 points

MacOS Big Sur, MacBook Pro 15 Late 2013, Thunderbolt Display

Following update to Big Sur, which also updates the firmware, my MacBook Pro 15 late 2013 will not boot if the Thunderbolt Display is connected. I can downgrade to Catalina but the firmware is not downgraded and the problem remains. I have reported it to Apple Support but wonder if anyone else is experiencing the same issue...

The system will boot correctly if the Thunderbolt Display is not connected

Connecting the display after boot the display works correctly on MacOS (which supports hot swop)

I use Bootcamp extensively and that does not support hot swop of the Thunderbolt Display so I

cannot use the display with Windows at all since updating (this is the big issue)

I have not found a reliable way of downgrading the firmware (which is where I believe the root cause of the issue lies)

Mike.

Windows, Windows 10

Posted on Nov 14, 2020 1:58 AM

Top-ranking reply

Donaldfromchippenham

Level 1

9 points

Posted on Nov 14, 2020 2:41 AM

Thank you. I'm glad I'm not alone or imagining things. I only wish I'd seen your post earlier!

I've had a very frustrating 24hrs trying to get Big Sur to work properly with my setup of MacBook Pro (Retina, 15-inch, Mid 2014) and 27" Thunderbolt display. The upgrade appeared to fail and booted to a black screen.

I reinstalled BS through (Command-R) and that didn't work.
I reset the NVRAM - no change.
Many restarts later, I discovered that it worked in stand alone mode when there were no external devices.
There were no issues with returning from sleep mode.
The Thunderbolt monitor works as normal but only if connected after MacBook has booted normally. On restart, boot will fail if still connected.

Many resets/restarts, shutdowns later, I have concluded that the issue is starting with the Thunderbolt display connected (and with it my ethernet connection and thunderbolt 2 connected Time Machine drive).

Since the Thunderbolt display is obsolete, I can't see Apple doing anything about its firmware. I hope they can find a work around as it's a pain having to reconnect every time.

I will report this to Apple as well.

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60 replies

ddkpe

Level 1

13 points

Nov 18, 2020 7:58 AM in response to ddkpe

More external display & device strangeness this morning during (cold) boot up - I had powered down my MBP last night.

FYI - I have a LaCie 2 Big Dock external RAID array connected via Thunderbolt 2/3 adapter & short cable to the back of my 27" Apple Thunderbolt display. It has been connected this way with no issues through all my previous Big Sur upgrade, Catalina restoration, SMC/PRAM reset and "display cable unplugging prior to boot" adventures. The external RAID array holds several storage/archive volumes, SuperDuper backups and my Time Machine backup.

With display cable disconnected, MBP boots up and I login and wait for the usual startup programs to complete. Upon plugging in the display cable I expected the external display to light up and the external disk volumes to be mounted - which is how it worked for the last few days. However, now the system freezes and then crashes during external disk mounting. ***?

I disconnected the external disk array from the external display, disconnect the display from MBP and booted up again. I get the external monitor to function after reconnecting the display cable, but now the system freezes & crashes when I connect the external RAID array to the external display. Double ***??

Do I now have a bad external disk volume that can't be mounted? I boot up the MBP with no external devices connected. I found a longer Thunderbolt 2 cable and connect the external RAID array directly to the MBP to check the disks. All the external disks mount and are OK.

I disconnect all external devices from the MBP and performed SMC and PRAM resets.

I returned my external devices to their usual configuration (external array daisy chained off the external display), and boot up with the display cable disconnected. Upon plugging in the display cable the external display lights up, then the system freezes and crashes during external disk mounting. More ***?

So I tried it a different way - reboot again with no external devices connected. Connected up the external RAID array directly to the MBP and all disks are mounted. Connected up the external display and it comes to life. Things are working again. System has not crashed (yet!) - I am using it to write this post.

Is this the new normal now? Figure out which combination external devices to connect & when after boot up?

This whole Big Sur upgrade experience has been fracking frustrating!

Nov 20, 2020 12:37 AM in response to Hussain9900

Hi, here are the written steps of downgrading from macOS Big Sur to Catalina:

https://www.globalnerdy.com/2020/11/18/how-to-downgrade-to-macos-catalina-after-upgrading-to-big-sur

If you have any questions before you start, please do post here. Next, if all goes well, you shouldn't loose any of your user related data because Apple has created a container that separates your internal HD (i.e. a container) into 2 volumes called MacIntosh HD (i.e. OS components) and MacIntosh HD - Data (i.e. all the user data). However, you may have to install and/or configure any applications. Finally, you should have backed-up everything that you care about before you begin this process even if it is just copying stuff to an external HD. Good luck and all the best.

Think different and code well,

-Conrad

OUM2303279 Author

Level 1

29 points

Nov 20, 2020 12:40 PM in response to ddkpe

After 3 sessions with very nice support people in Portugal, Ireland and lastly the US, uploading diagnostics twice, buying a new USB hard drive (I should have bought a USB SSD), installing Big Sur on the hard drive and uploading a video of the same failure on a clean install to do anything with the Thunderbolt Display connected... (obviously, the firmware was the same)

...I had a call back yesterday from the US support person saying that Engineering acknowledged the issue, they had several reports but don’t inform support of their plans to resolve issues. The support person went on to say that normally, acknowledged issues are resolved with an update or workaround (?) and that he’d be back in touch in a few days.

I wait impatiently for an update containing new/old firmware. Maybe 11.1 will have it when released? I have everything crossed.

So, many hours aside, I’ve spent real money on a hard drive and Parallels virtualisation software as a result of this firmware upgrade that can’t be rolled back just to report the problem and get some semblance of a useable system for my work but it is still not what it was. It is very annoying.

Dec 8, 2020 3:42 PM in response to Wall-0-Sound

I have the same issue on Big Sur with a 2016 MacBook Pro and 27" Thunderbolt screen. Can get the screen running but if Mac goes to sleep then I have to re-boot. Plus when thunderbolt camera, usb port's or speakers work. Its an awful thing to have a perfectly good piece of kit being made redundant by a company that is supposed to support recycling!

[Edited by Moderator]

Dec 8, 2020 5:10 PM in response to Wall-0-Sound

When I last spoke with my Applecare Senior Advisor last week, I was told that this is a known issue by the engineering team and a patch will be coming in a forthcoming release of macOS (i.e. Catalina & Big Sur). Why Catalina? If you upgrade to Big Sur, it will update to the newest boot ROM version. Now, if you downgrade to Catalina, it will not downgrade the boot ROM version back to the previous version. Thus, the issue that one experience in Big Sur will persist after downgrading to Catalina. In short, a patch will be created to resolve this issue at some point. Furthermore, I'm not planning to upgrade from Catalina to Big Sur again until mid February 2021 because this will give me some time to research application and hardware compatibility.

Dec 9, 2020 5:40 AM in response to OUM2303279

OUM2303279 wrote:

I'm sorry, I can't get past the annoyance of having my previously very functional Macbook and its many associated peripherals for both business and music rendered unusable by an 'upgrade' that has no way for me to safely back out.

If you had made a Time Machine Backup or a clone before the upgrade

(which you should be doing anyway for a business computer) you can

simply restore to the previous version. So there is a way to "safely back out".

And if you were not doing that, then it was an accident wait to happen, OS

upgrade or not.

Dec 9, 2020 5:48 AM in response to woodmeister50

The firmware for the thunderbolt screen has also been changed on Catalina when you upgrade to BIg Sur. So even if you do go back you get the same issues with that problem. This is why the fix has to be for both Big Sur and Catalina OS.

OUM2303279 Author

Level 1

29 points

Dec 9, 2020 6:59 AM in response to woodmeister50

Of course I have a backup.

The issue is that restoring to the previous version does not restore the firmware update that is installed with Big Sur. I'm pretty certain that the 'won't boot with Thunderbolt display connected' problem is due to the firmware (427.0.0.0.0). The boot process hangs in the EFI loader before it gets around to any operating system.

The firmware needs to be fixed. Only Apple engineering can deliver a fix and, according to Apple support, are "aware of the problem". I and others in the same position will continue to be annoyed until a fix is delivered

OUM2303279 Author

Level 1

29 points

Dec 14, 2020 10:45 PM in response to OUM2303279

The Big Sur update to 11.1 has updated my firmware to version 429.0.0.0.0 and this has fixed the problem for me (and, it would seem, for some - but possibly not all - others on this forum).

My MacBook Pro Retina Display Late 2013 once again can boot up with an Apple 27" Thunderbolt display attached. This means that I no longer have to boot into MacOs with the display disconnected, then connect the display when MacOs is running and more importantly, when I boot into Windows (Bootcamp) the display is recognised and can be used again. Hurrah!

Dec 15, 2020 12:54 AM in response to Donaldfromchippenham

I did that upgrade last night but it has not fixed - and did not say it would in the release notes , the camera and speakers not working on Thunderbolt screen. I have not experienced the crashes I was getting before but early days...

OUM2303279 Author

Level 1

29 points

Dec 15, 2020 1:52 AM in response to jackfromleigh-on-sea

Hi jackfromleigh-on-sea,

You are correct that the release notes make no mention of the firmware update or any fix to the Thunderbolt display booting problem. You have a different model MacBook to mine (on which the problem is definately resolved). Looks like you should revert to Apple Support.

Dec 15, 2020 2:13 AM in response to OUM2303279

Hi - yes I have already connected with Apple Support on this issue. I have a 2016 MBP. I am surprised - but pleased for you - that it works on rollback to Catalina as I thought the firmware fix was needed for both BS and Catalina.

OUM2303279 Author

Level 1

29 points

Dec 15, 2020 3:38 AM in response to jackfromleigh-on-sea

Just to be clear. I am on Big Sur. I believe that the firmware fix was distributed with both 11.1 Big Sur update and a similarly timed update to Catalina but I cannot be sure. Yes, I did roll back to Catalina from 11.0.1 Big Sur (actually back and forth twice!) in the hope that this would be a true roll-back but this is when I discovered that the firmware update is not rolled back and that there is no safe way to roll back firmware updates (there are reports that it can be done by de-soldering the relevant PROM chip and re-programming it with an external EPROM programing device but that is both unsupported and way over my level of competence). Good luck!

ddkpe

Level 1

13 points

Dec 15, 2020 9:29 AM in response to OUM2303279

I can confirm that the firmware fix is in the latest Catalina update too - I can now boot up my Mid-2014 MPB with my 27" Apple Thunderbolt display and other Thunderbolt & USB accessories connected. However, you will need to disconnect all those devices (for the last time) prior to installing the Catalina update - otherwise you will get the black screen again on the install reboot. Once the update installation finishes (about 25 minutes) everything works as expected again - no SMC or PRAM resets were required.

I also upgraded to Big Sur when it was released, and reverted back to Catalina via Time Machine. I will likely stick with Catalina until my backup utility (SuperDuper!) is released for Big Sur.

Dec 15, 2020 10:22 AM in response to ddkpe

Can you use camera and speaker on thunderbolt screen after this 'fix' ? only these threads are really confusing as I thought this one was just about camera and speakers and firmware - not just the thunderbolt screen connection boot up issue which is on another thread!!

MacOS Big Sur, MacBook Pro 15 Late 2013, Thunderbolt Display