You can now upgrade or downgrade BridgeOS on your Intel T2 Mac with an IPSW file & Apple Configurator 2!
As soon as Apple released the very first T2-equipped Mac, MacAdmins wished that they had a way to downgrade BridgeOS. You can now even downgrade BridgeOS on a T2 Mac up to 7 days after an update!
UPDATED: 6/07/22
BridgeOS IPSW Downloads
In the chart below is a list of previous BridgeOS IPSW files along with the signing status. (Signed = You can upgrade or downgrade) All links are Apple Software Update direct downloads.
| T2 Mac BridgeOS IPSW Download | OS | Signed | BridgeOS Version | Date | Unsig |
| 6.5_19P5071_Restore.ipsw | 12.4 | YES | 19.16.15071 | 5/16 | |
| 6.0_19P549_Restore.ipsw | 12.0.1 | NO | 19.16.10549 | 11/5 | N/A |
| 6.0_19P548_Restore.ipsw | 11.6.1 | NO | 19.16.10548 | 10/25 | 11/30 |
| 5.5_18P4759a_Restore.ipsw | 11.6 | NO | 18.16.14759 | 9/13 | N/A |
| 5.5_18P4759a_Restore.ipsw | 11.5 | NO | 18.16.14759 | 7/21 | N/A |
| 5.4_18P4663_Restore.ipsw | 11.4 | NO | 18.16.14663 | 5/24 | 7/26 |
| 5.3_18P4556_Restore.ipsw | 11.3 | NO | 18.16.14556 | 4/26 | 6/01 |
| 5.2_18P4347_Restore.ipsw | 11.2.2 | NO | 18.16.14347 | 2/25 | 5/03 |
| 5.2_18P4346_Restore.ipsw | 11.2 | NO | 18.16.14346 | 2/01 | 5/03 |
| 5.1_18P3030_Restore.ipsw | 11.1 | NO | 18.16.13030 | 12/14 | 2/08 |
| 5.0.1_18P2561_Restore.ipsw | 11.0.1 | NO | 18.16.12561 | 11/12 | 1/07 |
You can downgrade BridgeOS to one previous version (with in 7 days of a new os update) if you are having issues or would like to test the software update mechanism. The requirement for BridgeOS downgrade is that you need to satisfy the minimum OS Version or newer.
Why would anyone want to downgrade BridgeOS?
Example – You updated to macOS Big Sur 11.2.3 from 11.1. Something in the new version of bridgeOS is causing problems on your T2 Mac. You now want to downgrade to a previous version so you can single out the issue. You will need to downgrade macOS down to 11.2 to support the previous version of BridgeOS. If you downgrade BridgeOS to an older version than the installed OS then macOS Big Sur will not boot and you will be prompted to update BridgeOS from the macOS Update Assistant environment. After downgrading BridgeOS you will need to reinstall/downgrade 11.2 over the top of 11.2.3, or reinstall 11.2. You will now be running 11.2 and the matching bridgeOS version 18P4346.
NOTE! You can only downgrade back one previous version. Apple usually supports T-1*, current minus one version. *Apple will usually leave the previous version of BridgeOS signed for about 7 days after the release of a new update. The BridgeOS signing schedule follows iOS. (Apple will unsign previous versions of iOS about one week after a new update)
How to Downgrade BridgeOS on a T2 Mac
If you would like to learn how to do this, click on the link below!
https://mrmacintosh.com/how-to-downgrade-bridgeos-on-an-intel-t2-mac-with-apple-configurator-2/
T2 Macs from 2017-2020
| iBridge Product ID | DeviceID | Year | Description (Product ID) |
|---|---|---|---|
| iBridge2,1 | J137AP | 2017 | Apple T2 iMacPro1,1 (j137) |
| iBridge2,3 | J680AP | 2018 | Apple T2 MacBookPro15,1 (j680) |
| iBridge2,4 | J132AP | 2018 | Apple T2 MacBookPro15,2 (j132) |
| iBridge2,5 | J174AP | 2018 | Apple T2 Macmini8,1 (j174) |
| iBridge2,6 | J160AP | 2019 | Apple T2 MacPro7,1 (j160) |
| iBridge2,7 | J780AP | 2018 | Apple T2 MacBookPro15,3 (j780) |
| iBridge2,8 | J140KAP | 2018 | Apple T2 MacBookAir8,1 (j140k) |
| iBridge2,10 | J213AP | 2019 | Apple T2 MacBookPro15,4 (j213) |
| iBridge2,12 | J140aAP | 2019 | Apple T2 MacBookAir8,2 (j140a) |
| iBridge2,14 | J152FAP | 2019 | Apple T2 MacBookPro16,1 (j152f) |
| iBridge2,15 | J230kAP | 2020 | Apple T2 MacBookAir9,1 (j223k) |
| iBridge2,16 | J214KAP | 2020 | Apple T2 MacBookPro16,2 (j214k) |
| iBridge2,19 | J185AP | 2020 | Apple T2 iMac20,1 (j185) |
| iBridge2,20 | J185fAP | 2020 | Apple T2 iMac20,2 (j185f) |
| iBridge2,21 | J223AP | 2020 | Apple T2 MacBookPro16,3 (j223) |
| iBridge2,22 | J215AP | 2019 | Apple T2 MacBookPro16,4 (j215) |
Info shared with Rick Mark @su_rickmark & theiphonewiki.com/wiki/T8012
If you have any questions, you can post them below!
Hello I am a new Mac user from windows I came across your video and tried to unbrick my MacBook Air 2018 retina T2 chip which is displaying flashing folder with question mark, everything is how you explained I get into DFU no problem but when I go to restore it tells me it will upgrade the apple controller and erase my primary disk I continue the restore, it begins installing system and the target MacBook Air turns on then off and then DFU changes to a padlock and I notice at the bottom of the window Apple Controller has an exclamation mark in a yellow triangle next to it.
So I have hit a brick wall now and fear that my MacBook Air has a hardware issue stopping it from restoring although the reason it is like this is because I deleted partitions on the disk mistakenly.
I have a similar issue. And it’s not letting me boot to Recovery. Internet recovery fails.
Awesome, should have been there from the start, but it is still welcome now.
Having to have the systems permitted internet access to Apple servers was an unexpected issue compared with earlier Macs that you could just download a combo updater and do it all on an isolated network. The OS updates would just fail with a generic message – had to dig into the logs and spend hours working with Apple Enterprise support to get the message “Live internet updates are the only way”
This isn’t as good, but it’s better than only the “live internet” option to get an older piece of hardware at least mostly updated without having to expose it.
I haven’t had the need to go back on a BridgeOS update yet, but is good to know there is a window it can be done.
Hi, is there any blog on bridgeos itself ?