Big Sur & Bad Magic!

Same issue here with a 2020 (2018) Mac mini i5 and user-upgraded RAM to 16GB). What I have tried so far:

• Update Catalina to Big Sur (App Store, bootable installer)
• Clean-install to Big Sur (bootable installer)
• Update of a clean-installed Mojave to Big Sur (App Store, bootable installer)

All of this without success. The external boot settings were set accordingly, all to the lowest security settings available (https://support.apple.com/en-us/HT208198). FileVault off if that's relevant.

Boot into Safe Mode (How to use safe mode on your Mac - Apple Support) by booting with the Shift key held down and try downloading and installing from there.

NOTE: Safe Mode boot can take up to 10 minutes as it's doing the following; 

• Verifies your startup disk and attempts to repair directory issues, if needed

• Loads only required kernel extensions (prevents 3rd party kernel/extensions from loading)

• Prevents Startup Items and Login Items from opening automatically

• Disables user-installed fonts 

• Deletes font caches, kernel cache, and other system cache files

Apparently the affected computers need to be 'revived' by using Apple Configurator 2, posted by a Redditor: https://old.reddit.com/r/macmini/comments/jtohmr/bad_magic_error/

Here is the official guide by Apple: https://support.apple.com/en-gb/guide/apple-configurator-2/apdebea5be51/2.13/mac/10.15.6

No, I’ve never connected a eGPU. The only thing I can think of is that the current Big Sur installer (11.0.1) is causing these issues and is messing with the T2 chip - but I am only speculating.

I’m tempted trying a beta version of Big Sur but I don’t have time for all this in my free time. Apple needs to address this. Any way of making them aware of this? I know some folks on Reddit already contacted Apple support.

Thanks. Has anyone succesfully completed these steps and resolved the issue to upgrade to Big Sur ?

Hopefully it will also address poor / inconsistent Bluetooth on the mac mini 2018 (2019 purchase) as well which seems to be worse when it gets hot.

Go careful. I followed the instructions and I have now bricked my Mac Mini using a MB Pro which had Big Sur installed.

Now unable to revive or restore using Configurator 2.

No chime, no video. Configurator 2 can see the Mini but get error when trying to restore / revive.

Anyone else tried and been succesful ?

I also have a 2018 mac mini and ran into this issue. I spent hours online with support, who instructed me to do a firmware revive using Apple Configurator 2. This failed. That means my mac mini that was working fine prior to reaching out to them was now no longer working. I took it into the store for a genius bar appointment. They said they could get it working and it would take 24 hours. Less than a day later, they called and said I had to pay for a new logic board. So, now I have to pay $450 for a new part because it's been over a year since I bought it and I reached out to support for assistance. If you just bought it in July, you should be able to have them replace it within warranty.

This is crazy. I also spend hours on the phone with Apple yesterday and the day before. After trying basically everything I could do as a user, they suggested me to bring it in for service. Luckily I am still covered, but this issue seems to be introduced by Apple. Not sure how the chances are regarding a Mac mini service program, but obviously many users across the world are affected. If I was asked to pay I would probably hold off for now.

Other than that, here in Germany, they discouraged me to use Configurator. Both senior support employees suspect the issue to be the T2 chip.

Seems the issue with my Mac Mini was the OWC 32gig memory DIM.

The service center removed the DIM, used an Apple 4gig DIM and then was able to revive / restore and install Big Sur ? I have yet to try re-installing the 32 gig memory now that its operational, but will let you know.

Tino147, the authorised service centre replaced the 1 x 32 gig OWC stick with 2 x 4 gig kingston sticks and they were able to revive / recover it and install big sur. I have been using it with just the 8 Gig for the last week and it's been fine. I still have the OWC stick and will try it over the next couple of weeks to see what happens.

I've got 64gb(2x32) Crucial RAM. I upgraded after replacing the Logic Board. The issue occurred with the stock 8gb RAM on my mac mini. The local Apple store near me in Chicago had a Logic Board in stock and it was a $488 replacement after tax.

I had this problem. My Mac had third-party RAM installed. I put back in the original RAM supplied by Apple with the machine, and that fixed the problem. Could be coincidence though.

If you have third party RAM installed, I suggest try going back to the original modules if you still have them, before attempting the Configurator approach. There may not be a problem with the T2 chip after all.

Good luck!

Hi there, thanks for sharing your experience. It turned out that exactly your solution also worked for me.

So I originally bought my i5 mini with 8GB RAM directly from Apple and upgraded to 16GB Ram (Crucial) myself. Everything worked fine as long as I sticked to Mojave or Catalina. When attempting to update to Big Sur, I had the BAG MAGIC error - I tried installing Big Sur any possible way (but kept my fingers off the revive procedure).

Until I read your comment, I did not consider returning to the original RAM sticks because some other user reported it not to be successful. Anyway, I just gave it a shot this morning because all apple service centres are closed for at least two more weeks (lockdown). Now I am writing this comment from macOS 11.1. Thank you.

I'll re-install the 16GB stick to have my increased memory back, but still curious to know If future security updates are affected. Will update if I run into issues again.

Following up on my last post. As I said, the third-party RAM caused the error message for me. I could update to Big Sur by temporary installing the original RAM. After successfully updating to Big Sur, I opened the mini up again, removed one of the original sticks and replaced it with the 16GB crucial which caused the problems. So my mini has 20GB installed in total (yes this is possible, IMO additional ram beats any dual-channel considerations). With this setup, the update from 11.1 to 11.2 was hassle-free, and everything worked as expected.