Studio Display Stuck in Endless Loop While Updating to iOS 15.4

Hi, I called Apple and went thru some troubleshooting with them but we're unable to get it resolved. The guy I spoke to thought it could have something to do with Filevault preventing the update. He suggested I take it to an authorized repair center, which I did.

They had a look at it and connected it to one of their MacBooks to do the update. Same issue happened, except that in the System Report the Studio Display did show up - whereas in mine it didn't. They tried multiple things and went thru more testing with Apple Support, to no avail. Apple Support escalated it to Engineering, who were going to respond in a day or two.

The Repair Center gave me the choice of collecting it and taking it back to the retailer I bought it from (along with a report confirming the unit was faulty) so I could exchange it; or wait for Engineering to respond with a fix which may involve changing out the logic board. That's if parts are actually available, and the repair time was unknown.

I obviously chose to exchange it, which I did yesterday. When I got home I hooked it up and checked the software version, which was iOS 15.3. I was a bit worried about updating it just in case the same thing happened, but I tried it anyway. I got an error message saying it was unable to update software and to try again in an hour. I decided to leave it and was going to try again today but ran out of time.

If you are having exactly the same issue as I was, I'd take it back and get it exchanged if you can. It appears Apple does not have a solution as yet or may not be aware of the problem. Would be interesting to know how many others this has happened to. I really didn't expect to have a problem, especially considering the fortune I paid for it....

I tried to upgrade my replacement monitor last night and exactly the same thing has happened again. Spent three hours on chat with Support trying all sorts of things - turned off firmware password and Filevault, rebooted in safe mode, unplugged cables and power, etc, but nothing. Senior Support are calling me today.

The interesting thing is that when I went to System Report and had a look at Graphics the Studio Display is not showing anymore. When I click on Thunderbolt it shows it is connected and it says it is a Studio Display.

I've got nothing else plugged in to my MacBook. The Thunderbolt 2 cable I'm using is a genuine Apple one and the Thunderbolt 2 to Thunderbolt 4 adapter is also a genuine one.

I'll be really ****** if I have to trek across town yet again to take this to a repair agent or switch it over at the retailer again.

I tried everything you did with the same cables and adapters, etc but unfortunately I didn't have another MacBook to use to try the upgrade, but when I took it to the repair center they tried with several other Macs they had there and it would not upgrade at all.

Just to update on my previous message, I was contacted by Apple's 2nd Level Support and spent a bit of time going thru things. He accessed my Mac remotely and collected the logs to try to figure out what was going on. Then he realized that I was using a mid-2015 MacBook Pro, which is NOT on the list of Studio Display compatible devices - which is weird because I swear it was when I originally checked the Apple site a couple of weeks before the Studio Display was released, otherwise I would not have bought it.

He said that as the display was not compatible, it should not have even been able to initiate an update at all but it did. He was stumped as to why it did, but he was going to escalate it to the Engineering Team and advise them and hopefully they will make the necessary modifications to the software to carry out the right compatibility checks before allowing an upgrade to proceed. Despite bricking two brand new NZD$3000 displays and going back and forth between the repair center and the retailer, I'm quite happy that being the first person Apple has come across who has had this issue, it was identified and they are now able to ensure others don't have the same problems.

Just going off what I have read. Maybe give these guys a call and get them to correct their articles with the right terminology...

https://www.techradar.com/nz/news/apples-studio-display-is-found-to-be-running-ios-154-is-this-the-27-inch-imac and https://www.macrumors.com/roundup/studio-display/ under "A13 Chip"

Apple personnel didn't appear to be aware of the compatibility. I spoke to several people there, including Level 2 and all were told that I had a mid-2015 MacBook Pro. Like I said earlier, I am certain that when I originally checked a couple of weeks prior to release, the specs said my model was compatible otherwise I would not have bought it. I'd love to be able to find the proof of it!

Apparently the Studio Display runs a full version of iOS on it. The ones shipped at launch had iOS 15.3 on it and then our Macs advised an update to 15.4 was available for the Studio Display.