Tahoe - Intel UDH 630 - dual monitor problems

[fermento]

@verdazil

 

Ok. very interesting test 👌

 

1. When I boot with the output set to HDMI, same flickering behavior, when the system reaches the login screen, black screen output for a while, then flickering, then stabilization.

2. When I boot with the output set to DP, the system reaches the login screen without issues, I immediately switch to HDMI output and the screen is stabilized, no flickering at all.

Edited January 7 by fermento

[deeveedee]

@verdazil Interesting. How is this test different from previous tests that booted successfully with a single monitor, then connecting the second monitor after booting? The results were the same and did not require lspcon. No?

 

EDIT: And these were the results with the adapter.

 

@fermento please correct me if I'm wrong.

Edited January 8 by deeveedee

[verdazil]

@deeveedee, You just need to connect a second monitor via HDMI - HDMI cable and everything will work perfectly. You just need a different monitor, not the Dell E248WFP.

 

3 hours ago, verdazil said:

The user and I have the exact same motherboard and integrated graphics. If I disable lspcon, my second monitor doesn't work. So lspcon is required

Do you understand this logic?

[deeveedee]

@verdazil Fermento said he already tested a Samsung display with HDMI -> HDMI and the behavior was no different (flickering) when booting with both displays connected.

 

Your test only seems to test that the system boots fine with a single display connected and then the second display connected after booting (which was already tested and confirmed to work).

 

What we need to see is both displays connected and enabled during boot.

 

If I am misunderstanding your test and the results, please accept my apology.

 

Hopefully this is explained when fermento takes your recommendation and boots with two displays where one is HDMI->HDMI and the other is DP->DP (which he has already done).

[fermento]

Hello, how are you?

 

Since I can't understand how @verdazil came to these conclusions, I ran multiple tests again with your configuration (config-UH60).

 

Single Display Tests:

1. Gigabyte M27Q through DP -> working flawless
2. Gigabyte M27Q through HDMI -> working flawless
3. Samsung Tv through HDMI -> working flawless
4. Dell through HDMI -> DVI adapter -> working flawless

 

Multi Display Tests:

1. Gigabyte M27Q through DP + Samsung Tv through HDMI -> flickering issues .... endlessly loop to stabilize (3 minutes and counting), ended up unplugging the HDMI from the motherboard and plugging again with occurs in an instantly stabilization.
2. Gigabyte M27Q through DP + Dell through HDMI -> DVI -> flickering issues, stabilized around 1 minute.

 

So, after the tests, MY CONCLUSION is that there are no hardware problems, neither the Dell monitor, neither the adapter, neither the cable.

 

@deeveedee Let me know if you come to the same conclusion or a different one.

 

Demos attached below in SUPER low quality and fps dropped for size purpose. If someone needs the real data we can see how to share them.

Edited January 8 by fermento
Typo

[verdazil]

9 hours ago, fermento said:

So, after the tests, MY CONCLUSION is that there are no hardware problems, neither the Dell monitor, neither the adapter, neither the cable.

There are hardware issues, but they're not critical. During boot, macOS struggles to find a working video mode. While it's doing this, there are delays, flickering, and so on.

My monitors are new and more compatible with macOS. I use high-quality cables and don't use any adapters. macOS boot is smooth, synchronous on both monitors, without delays or flickering.

[deeveedee]

The DVI-D displays connected to my HackMini8,1 are ancient Dell displays with VGA and DVI-D inputs and I am using DP->DVI-D adapters. They work perfectly with macOS.  My own experience to find a working framebuffer patching solution was more tedious than this one has been so far, so I don't think that we have exhausted framebuffer patching options.  There may be hardware issues (which is to be expected with hackintoshes and these displays are obviously not modern Apple displays), but I am still hopeful that these can be resolved with framebuffer patching.

 

Please answer the following:

• Did you test enough to determine that enabling or disabling lspcon does not make any difference on this hack?
• Do we agree that this hack boots fine with a single display connected (regardless of whether it is HDMI->HDMI or HDMI->DVI-D)?

[fermento]

8 hours ago, verdazil said:

There are hardware issues, but they're not critical. During boot, macOS struggles to find a working video mode. While it's doing this, there are delays, flickering, and so on.

My monitors are new and more compatible with macOS. I use high-quality cables and don't use any adapters. macOS boot is smooth, synchronous on both monitors, without delays or flickering.

 

Ok, seems that you have a Mac without logo not a hackintosh because your hardware is high quality and 100% compatible with macOS. Despite that, I don't see any oficial list from Apple for External monitors compatibility. I assume they support all, not only the super new monitors, because that's the purpose of that feature "external monitors" not "external APPLE monitors".

 

By the way, you are saying that the hardware has issues because, during the boot process, my computer has delays, flickering and so on. So, how do you explain that when I have only one display connected, I'm already logged in, and I connect the Dell display, has not issue at all, works flawlessly? I assume if my hardware has issues that should not be possible.

 

@verdazil

Beyond that, I think you've been a little rude to @deeveedee, and I don't see the need for it. We're all here trying to solve a problem with the hackintosh, contributing possible solutions. I don't see the point in fighting or thinking you're better or worse than someone else. Especially not in treating someone else badly.

 

I hope we can all continue to seek solutions by treating each other well and, if we have any criticism, that it be constructive rather than destructive.

[fermento]

On 1/9/2026 at 10:23 AM, deeveedee said:

Please answer the following:

• Did you test enough to determine that enabling or disabling lspcon does not make any difference on this hack?
• Do we agree that this hack boots fine with a single display connected (regardless of whether it is HDMI->HDMI or HDMI->DVI-D)?

 

1. I don't know because I barely know lspcon, I'm open to test any config to have more conclusions around lspcon.
2. I agree with that! At least, the 4 tests I did with single display confirm this.

[deeveedee]

@verdazil Please accept my apology for the way I acted. I'm sorry.

 

Would you be able to continue to help fermento to test lspcon? I'm not sure what else about lspcon he needs to test.

 

Thank you.

[verdazil]

6 hours ago, deeveedee said:

Please accept my apology for the way I acted. I'm sorry.

We're here because we're interested in this, and we're doing what we love. Sometimes misunderstandings arise, but that's normal.

Unfortunately, I was not always polite and correct either.

 

6 hours ago, deeveedee said:

Would you be able to continue to help fermento to test lspcon? I'm not sure what else about lspcon he needs to test.

 

I don't know how else I can help... The settings I've published have been thoroughly tested and confirmed to work. User may experience some issues due to using older equipment and an adapter...

Edited January 12 by verdazil

[Asural]

1 hour ago, verdazil said:

I don't know how else I can help... The settings I've published have been thoroughly tested and confirmed to work. User may experience some issues due to using older equipment and an adapter...

I think if @fermento is testing the EFI attached to this post, he needs to consider whether the contents of the EFI are suitable for Tahoe.
Only you can do that.
 

ADD:

Regarding EFI:
1. Disable wireless use and settings, and focus on basic operation only, so you can concentrate on screen adjustments.
2. Are the APCI contents and settings correct?
3. Select only the necessary kexts.
4. Are the USBMap settings correct?

 

Questions regarding connected devices:
Can WEG handle HDMI 2.1? Is HDMI 2.0 necessary?
 

Edited January 12 by Asural

[verdazil]

2 hours ago, Asural said:

Questions regarding connected devices:
Can WEG handle HDMI 2.1? Is HDMI 2.0 necessary?

At present, macOS:

- does not have driver-level support for HDMI 2.1

- does not implement FRL (Fixed Rate Link)

- operates only within the TMDS model (HDMI 2.0 class)

 

Even on real Macs:

HDMI 2.1 as a protocol is not used, the maximum is HDMI 2.0 (18 Gbps)

 

WEG can:

- remove the pixel clock limit (HDMI 2.0 / 4K@60)

- correctly enable and configure LSPCON (DP → HDMI 2.0)

- fix EDID and connector-type issues

- make HDMI operate as 2.0 instead of 1.4

 

WEG cannot:

- enable FRL

- turn HDMI 2.0 into HDMI 2.1

- provide 4K@120, 8K, or DSC over HDMI

- add VRR / ALLM / QFT support

 

HDMI 2.1 is backward compatible with HDMI 2.0 and earlier versions.

[verdazil]

2 hours ago, Asural said:

Regarding EFI:

Everything is fine with this @fermento 's EFI for Tahoe. There's just one extra kext: XHCI-unsupported.kext and an inappropriate framebuffer patch.

Edited January 12 by verdazil

[Asural]

26 minutes ago, verdazil said:

Everything is fine with this @fermento 's EFI for Tahoe. There's just one extra kext: XHCI-unsupported.kext and an inappropriate framebuffer patch.

"Follow me and you'll succeed" is fine, as I see it, but I have doubts about ACPI's Power Management.
There are also conditions for USBMap that I'm not familiar with.
I think we should get it working under conditions that you can guarantee, and then discuss additional features.

 

The conversation has progressed to "under what conditions is LSPCON necessary?", but you first need to state your operating conditions and have others follow them.
Only you can say, "This is how it will work."
 

[Asural]

36 minutes ago, verdazil said:

@Asural,  You're complicating things. There's a reference configuration (which I followed). Here's the link.

https://github.com/5T33Z0/Gigabyte-Z490-Vision-G-Hackintosh-OpenCore/releases

Don't follow me, follow the link. I just added the framebuffer patch for my and @fermento motherboard revision, which was previously published.

You'll probably need to check your BIOS settings, but let's hope @fermento follows the instructions in the link.
By the way, it seems that LSPCON is limited by the refresh rate, but does your MDMI monitor support more than 60fps?
 

[deeveedee]

@verdazil and @Asural That link is how fermento started.  Notice that the latest updates in that link apply to a hack with a dGPU, not iGPU.  It appears to me that 5T3ZZO abandoned iGPU configuration and did not get it to work properly.  We should not be following that link for iGPU settings.  The notes about WhateverGreen are not relevant to this hack.

 

@fermento I am going to propose some new tests for you.  The tests I propose will be based on my own opinion that we can resolve this problem with framebuffer / connector flags.  My baseline will be the simplified DeviceProperties that we established earlier in this thread.  Since we are in a public forum with each of us able to express our own views and opinions, it will be up to you to pick and choose the advice that you will follow and the suggestions that you will test.  Based on what I've seen, you won't have any problem with that.

 

 

Edited January 12 by deeveedee
Fixed typos

[verdazil]

5 minutes ago, Asural said:

does your MDMI monitor support more than 60fps

My main monitor supports up to 160 Hz/4K in macOS via RX 6600 && DP, but no more than 60 Hz/4K via DP or HDMI via LSPCON. But this is not a limitation of LSPCON, it is a limitation of UHD 630.

 

See Intel® UHD Graphics 630 specification:

4K Support - Yes, at 60Hz
Max Resolution (HDMI)‡ - 4096 x 2160@30Hz
Max Resolution (DP)‡ - 4096 x 2304@60Hz

[verdazil]

45 minutes ago, deeveedee said:

 Based on what I've seen, you won't have any problem with that.

Agreed. Since there’s nothing further I can contribute beyond what’s already been said, I’ll leave it here.

Just one more important reminder. The user linked to in the previous message has a motherboard revision 1.0. He doesn't need the LSPCON patch. @fermento and I have MB revision 1.1. We need this patch.

Edited January 12 by verdazil

[deeveedee]

@fermento The attached config.plists are based on config-test5-4.plist which you previously tested and reported that it has the "flickering" problem.  These config.plists have the following modifications:

• config-test5-6.plist: con0/con1 flags changed to 0x00c7

• config-test5-7.plist: enable lspcon on con1 with framebuffer-con1-preferred-lspcon-mode=1 (HDMI 2.0)

• config-test5-8.plist: enable lspcon on con1 with framebuffer-con1-preferred-lspcon-mode=0 (HDMI 1.4)

 

config-test5-6.plist.zip config-test5-7.plist.zip config-test5-8.plist.zip

[Asural]

On 1/8/2026 at 5:25 AM, fermento said:

 

Tested your config, flickering issues during login

 

1. HDMI cable 2.1

2. Displays

  2.1. Gigabyte M27Q - 2‎560 x 1440 (QHD)

  2.2. Dell E248WFP - 1920 x 1200 FHD

3. Revision 1.1

You're all suspicious of HDMI, but are you using a DP2.0 DP cable?

[fermento]

23 hours ago, verdazil said:

There's just one extra kext: XHCI-unsupported.kext and an inappropriate framebuffer patch.

 

Removed XHCI-unsupported.kext and changed the framebuffer patch to match the repository. Also, changed the SystemProductName to iMac20,1. The flickering issues still happening. I will store this config apart to test again during this week replacing the Dell with a relative new Tv HDMI - HDMI directly.

 

By the way, 5T33Z0 was always my reference since I bought this motherboard.

 

21 hours ago, verdazil said:

My main monitor supports up to 160 Hz/4K in macOS via RX 6600 && DP, but no more than 60 Hz/4K via DP or HDMI via LSPCON. But this is not a limitation of LSPCON, it is a limitation of UHD 630.

 

Can you expand on this? The M27Q is 2560 x 1440 @ 170Hz right now through DP and the Dell 1920 x 1200 @ 60Hz through HDMI.

[fermento]

21 hours ago, deeveedee said:

@fermento The attached config.plists are based on config-test5-4.plist which you previously tested and reported that it has the "flickering" problem.  These config.plists have the following modifications:

• config-test5-6.plist: con0/con1 flags changed to 0x00c7

• config-test5-7.plist: enable lspcon on con1 with framebuffer-con1-preferred-lspcon-mode=1 (HDMI 2.0)

• config-test5-8.plist: enable lspcon on con1 with framebuffer-con1-preferred-lspcon-mode=0 (HDMI 1.4)

 

config-test5-6.plist.zip 6.31 kB · 2 downloads config-test5-7.plist.zip 6.34 kB · 2 downloads config-test5-8.plist.zip 6.34 kB · 2 downloads

 

• config-test5-6 -> not able to reach the login screen, the system reboots after a few seconds
• config-test5-7 -> flickering issues
• config-test5-8 -> flickering issues

[fermento]

@verdazil

 

This is another test I just did. The Dell display with the same HDMI cable connected to my macbook pro through HDMI as extended display.

[deeveedee]

3 hours ago, fermento said:

 

• config-test5-6 -> not able to reach the login screen, the system reboots after a few seconds
• config-test5-7 -> flickering issues
• config-test5-8 -> flickering issues

 

Based on your test results, framebuffer-conX-flags bit CNUsePowerWell2 (defined here) is required for your hack.  I don't have any further lspcon settings to test, so I'll be looking at other settings.  I don't want to discourage you from doing more lspcon testing - I'm just saying that I won't be offering any more lspcon testing suggestions.

 

Now that brumas2025 dual displays are working well, I remain confident that framebuffer patching is still possible for you.  I need to review the tests in this thread before I propose new tests for you.

Edited January 13 by deeveedee
Fixed typos