Big Sur random screen freezes with green lines then restart

[elgipsy]

Check that the generated serial is clean.
If yes, start using the new system definition and boot in to macOS.
Log in to iCloud.
Go to System Preferences > Apple ID.
Look for your old iMac20,1 system and delete it from your account.

Ok

And when I get a GPU, i change ID’s again and remove macmini8,1 system from my account, correct?
Can’t I just leave my iMac there? It will be offline anyway and I’ll use it only after I find a GPU?

One more question: what about ROM value? I’m using the one from my network card with the iMac. Should I use the one generated with GenSMBIOS instead?

 

[pastrychef]

And when I get a GPU, i change ID’s again and remove macmini8,1 system from my account, correct?

Yes.

Can’t I just leave my iMac there? It will be offline anyway and I’ll use it only after I find a GPU?

That should be fine too. But I just like to keep all that as clean as possible. I have so many devices listed there...

 

[elgipsy]

Hi there,

Here's an update since I switched from iMac 20,2 to Mac mini 8,1. The system is definitely more stable but random freezes still happen out of the blue but now the lines are red instead of being green.

I think I have isolated the issue and that it will happen when I use Safari and watch videos (can be YouTube or anything else). I'll try Chrome for a few days to see if it happens again, if it does I'll try one more clean install from scratch with clean BIOS

 

[elgipsy]

Hi there,
Still facing these random freezes and reboots with a Macmini 8,1 system definition. When the system freezes, there are either green, blue or red lines and it only happens with the hack, not when I run Windows.

I had another look at OC's guide and even though it is recommended to use iMac 20,2 for i9 10850k or higher under Comet Lake section, it is also mentioned under Extra>Choosing the right SMBIOS that:

• iMac20,2 is a custom SMBIOS meant only for Apple's custom i9-10910 CPU, so unless you have an i9-10900K we recommend using iMac20,1
• Mac Mini SMBIOS should be avoided unless you're running mobile hardware without a built-in display
  • Intel NUCs are the ideal hardware for this SMBIOS

As I am not using a NUC, I'm wondering if I should try iMac 20,1 SMBIOS? Or make a change in the plist or in BIOS related to the iGPU?

I'm really lost, hope someone can assist further...
Thanks!

 

[Edhawk]

You just answered your own question! And provided a solid reason for not using the Macmini SMSBIOS.

Yes, you should try the other iMac SMBIOS to see if it helps.

 

[elgipsy]

You just answered your own question! And provided a solid reason for not using the Macmini SMSBIOS.

Yes, you should try the other iMac SMBIOS to see if it helps.

@Edhawk

Thanks for your reply Edhawk. The thing is that I do not have a gpu for the moment and iMac 20,1 has one (RX580), that's why I went for Macmini 8,1 as it has an UHD 630 igpu like the Macmini. Won't there be issues if I use iMac20,1 without a gpu?

UtterDisbelief and pastrychef suggested I disable xmp which I haven't done yet; I should try but as Windows is stable it might not be the issue.

 

[Edhawk]

Using the Macmini SMBIOS makes sense, but more so for a Coffee Lake system. Trying the other iMac SMBIOS is to my mind also worth a try. You won't know what difference it will make until you try it. Some SMBIOS's work just fine in an IGPU only setup.

Your system will be using DDR4 RAM, it probably wouldn't make a noticeable difference if you disabled XMP. So again this is worth investigating.

Sometimes the simplest/smallest changes make a huge difference when running a Hack.

Do not compare how well your system runs using Windows, as that is what it was designed to do. Running macOS on a PC is not comparable, as they use different settings, drivers and processes to undertake similar tasks. This is a mistake that a lot of people make.

These are two separate OS's, which work in different ways to produce similar (not identical) processes. They should never be compared in a straight process v's process manner. Never assume that because something works in Windows it will work in macOS. It may work if the device is compatible with macOS and there are kexts available for the version you are running. But even then it is not always as straightforward as you might think.

 

[elgipsy]

Thanks @Edhawk I'll try iMac 20,1 and see what happens; just need to get serials, sign out of services on the hack and reinstall macOS with the new serial and see what happens. One question though, Ive seen that GenSMBIOS also generates ROM value; is it safe to use? I can use my ethernet card's ROM but as I've used it already I wonder If this could create problems?

 

[elgipsy]

Weill tried Imac20,1.... and I got those lines again, dunno what to do

 

[Edhawk]

I've had a look at your EFI folder from post #3.

You have two SSDT's that I wouldn't expect to be required for your Z490 system, SSDT-DTPG.aml and SSDT-SBUS-MCHC.aml. I would recommend removing these two SSDT's to see what difference that makes.

You have a Thunderbolt port on your rear I/O plate, do you use it? If yes, what is connected to the TB port?

I looked at the USBPorts.kext setup and notice that you don't have a USB Type-C port included in the configuration, if the TB Type-C port is being used as a USB port then it needs to be included in the USBPorts.kext.

The Drivers, Resources and Tools folders are fine for how you are using and booting the system, i.e. using the OC Picker List.

Your config.plist requires a couple of IGPU framebuffer entries, and there are a number of placeholder entries that can be removed.

I have edited the config to match the recommendations in the OC guide, removing the two SSDT entries, adding the Framebuffer entries and removing any placeholder/unnecessary entries.

Add your SMBIOS iMac20,2 data to the config and see if that helps any.