Post-14.7 kernel panic

TidBITS Talk
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Well, it appears that my kernel panics aren’t done. Even though I seemed to have successfully rolled back my system to 14.6.1, and I am no longer getting a kernel panic within a few minutes after a reboot, I just suffered another panic today (5-6 days later).

I was able to make a copy of the panic log files, and I noticed this at the top (pretty-printed for readability):

{
    "roots_installed":0,
    "caused_by":"bridgeos",
    "macos_version":"Mac OS X 14.6.1 (23G93)",
    "os_version":"Bridge OS 9.0 (22P353)",
    "macos_system_state":"running",
    "incident_id":"3289D24D-F64B-4AA4-AADD-3549D407F296",
    "bridgeos_roots_installed":0,
    "bug_type":"210",
    "timestamp":"2024-09-21 19:06:35.00 +0000"
}

BridgeOS is the firmware running in the T2 chip. I think rolling back to 14.6.1 did not roll-back the BridgeOS firmware. But I have no way of knowing what version of macOS “Bridge OS 9.0” belongs to, nor do I know of any way to get the previous version to attempt a rollback (which I think can be done with Configurator).

If anyone has a clue about what to do next, please let me know.

Do you think maybe it would be best to upgrade to macOS 15, in the hopes of getting an even newer BridgeOS firmware?

Update: It happened again, several minutes into running a backup with CCC (what I was doing when the previous panic happened). It looks like there’s some kind of race condition in BridgeOS that is panicking my (2018 Mini) Mac under heavy amount of file system access.

Or maybe trying to access some specific file? Does CCC has a log that might let me see what it was backing up at the time of each panic?

For now, I’m thinking that I’m going to have to just rely on Time Machine for my backups (which has been working fine all week) until another macOS update ships that may have a newer BridgeOS release. Which, needless to say, really bothers me.

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Interestingly, the version of BridgeOS reported in System information is not 9.0, but “iBridge: 22.16.10353.0.0,0”:

Screenshot 2024-09-21 at 16.48.05
Screenshot 2024-09-21 at 16.48.05789×512 80.1 KB

According to Mr. Macintosh, 14.6.1 uses the same BridgeOS as 14.6: 21.16.6074.0.0.

So I’ve definitely got a newer one installed, almost certainly from the 14.7 update.

But even if I can get the older image (which Apple is probably going to stop signing today or tomorrow), I can’t install it because my only other Mac (from which I’d run Configurator 2) is too old to do the job.

At this point, I’m thinking that the only real option I have is to wait for a macOS update newer than 14.7/15.0 and install that upgrade if it ships with a newer BridgeOS release.

According to MacRumors, 15.0 includes the same system firmware version I’ve got right now, so that upgrade won’t help either.

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As you said, running Configurator 2 if you had a suitable machine would be the thing to do. I’d be nervous about trying to run a newer software update using the regular update mechanism if you’re not in a stable configuration due to BridgeOS, but that’s probably your only alternative if the system is crashing often and you can’t use Configurator 2. Any chance you can borrow a machine from somewhere to run Conf 2?

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Sadly, I don’t have a modern-enough Mac available. I could probably go to an Apple Store, but it’s likely that the older firmware won’t be installable tomorrow, since Apple stops signing them pretty quickly, like they do for iOS.

When the time comes to install the next update, I’ll boot to safe mode (which seemed stable when I was running 14.7 on Monday) and run the installer from there.

And I still can’t figure out why it’s possible to upgrade BridgeOS from a running system, but they force you to use Configurator to downgrade. Clearly, it’s not a technical limitation, but a deliberate business decision.

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On Intel Macs you cannot roll back firmware. That’s an Apple silicon only feature.

Once you update the firmware on an Intel Mac, the only way to resort issues is to await the next firmware update and pray it fixes whatever broke last update.

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Howard Oakley mentions on his site that T2 Intel Mac’s can roll back the iBridge firmware if it’s within the seven days overlap. Not sure if this can help the OP:

Unlike Apple silicon Macs, T2 models can normally only refresh or restore the current iBridge firmware. Apple does leave an overlap period of seven days during which both the previous version of iBridge and a newly released version remain validly signed, but once that has expired there’s no way to downgrade T2 firmware.

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That’s a fairly old article. He has revised since.

Intel Macs have one significant limitation here: firmware. While you can roll the system back, you can’t return an Intel Mac’s firmware to a previous version. So if the problems you’re encountering are firmware-related, your Intel Mac is out of luck.

Apart from few rare exceptions, on an Intel Mac you cannot install old firmware over new. This is an important difference to Apple silicon where, once quipped with the proper IPSW, you can install pretty much whatever you want (assuming it’s not older than the Mac of course). A great source of IPSW including for older versions BTW is Mr. Macintosh.

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The article I mentioned is not that old, only a bit over a year ago and I don’t see any correction which I think he would have made had the information regarding the T2 issue proven incorrect.

The later article is more about installers which is a different issue for the OP.

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Howard Oakley has posted precisely today a couple of articles about firmware versions:
https://eclecticlight.co/2024/09/23/which-firmware-should-your-mac-be-using-version-8-sequoia/
I have just skimmed through one of them, but it seems that Configurator 2 is not needed for Sonoma (at least to solve some kinds of problems) though another Mac running at least Monterey is required.

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Now that Apple has dropped seeds for the 15.1 and 14.7.1 update (source: MacRumors and the accompanying article’s discussion thread), does anybody here know if it includes a BridgeOS/iBridge update for Intel Macs? (Assuming beta testers can legally say anything - if not, please don’t violate your NDA by reporting it.)