How To View Boot Log After Kernel Panic During Boot

[liamwachs]

Heya everyone.

I recently completed my first build using @CaseySJ 's guide. Pretty much everything is working perfectly except I am getting some KP crashes during boot every so often. Once I reboot it always boots fine on the second attempt. I can't seem to be able to work out how to scroll up so that I can see the whole log during the crash or find the log anywhere once I've rebooted successfully.


This is what I've got set for the boot. I am seeing the bottom of the log once it happens but can't scroll up.


Here is a photo of the bottom of the log.


Any help finding the full log so that I can post it on here would be much appreciated.

Cheers

 

[jaymonkey]

@liamwachs,

When a KP occurs the file system in inaccessible so Kernel Panic log's are written to NVRAM.

As long as you have native NVRAM enabled (it does not work with emulated NVRAM) you can view the KP log file on the next successful boot once you see the message "Your computer was restarted because of a problem" :-



Click on "Show Details" to view the KP log file.

If the KP is occurring during boot up (using verbose mode) there is no way to scroll up, the only way (other than the above method) is to make a video of it ... if your camera/phone has a high FPS mode then you should use it and playback in slow motion.

Cheers
Jay

 

[liamwachs]

@liamwachs,

When a KP occurs the file system in inaccessible so Kernel Panic log's are written to NVRAM.

As long as you have native NVRAM enabled (it does not work with emulated NVRAM) you can view the KP log file on the next successful boot once you see the message "Your computer was restarted because of a problem" :-

View attachment 472387

Click on "Show Details" to view the KP log file.

If the KP is occurring during boot up (using verbose mode) there is no way to scroll up, the only way (other than the above method) is to make a video of it ... if your camera/phone has a high FPS mode then you should use it and playback in slow motion.

Cheers
Jay

Thanks very much for the reply @jaymonkey.

I never see that message after I reboot. It just works fine the second time. How can I find if have enabled native NVRAM?

So will it not show up in my Hackintool boot log if there was a KP during boot?

Sorry for the immediate follow up questions.

 

[jaymonkey]

@liamwachs,

If you do not see the "Your computer was restarted because of a problem" message then either the KP occurred too early in the boot process for it be logged or NVRAM is not working.

You can test if NVRAM is working by creating a temporary variable by running the following Terminal command : -

sudo nvram TestVar=HelloWorld

Now reboot and run the following Terminal command

sudo nvram -p | grep 'TestVar'

If you see the result HelloWorld then NVRAM is working.

However as I said if you are using emulated NVRAM then KP logging will not work as emulated RAM relies on MacOS writing the contents to a plist file on a reboot or shutdown via a system script.

Emulated NVRAM uses the EmuVariableUefi efi driver which will be present in the /EFI/Clover/Drivers/UEFI folder if installed and you will also see the file nvram.plist present in the root of the EFI folder.

Cheers
Jay

 

[liamwachs]

@jaymonkey Thanks very much for the info. I do indeed have nvram.plist in the root folder.
I'm going to look into getting the proper NVRAM working via CaseySJ's guide.

Thanks very much for the help.

Also weirdly the main issue I was having was that it wouldn't wake up after going to sleep, then I would restart it and then it would crash.

I just got a different monitor and now the sleep seems to be working totally fine... No idea why.

 

[jaymonkey]

@liamwachs,

I believe that there are/was known issues with getting native NVRAM working on certain Z390 motherboards.
However its been a while since i read up on it so it possible that more progress has been made since then.

I don't have a Z390 system so am unable to test or advise much more beyond what i already wrote above.

Cheers
Jay

 

[liamwachs]

@jaymonkey

All good. It seems doable via CaseySJ's guide with a Z390.

Thanks very much for the guidance. It's very much appreciated.