HP 800 G4 DM UHD 630 DP connection black screen and flickering issue

[cass]

Hello everyone,

I have an HP 800 G4 DM (i5-8500, UHD 630) running macOS Sequoia 15.7.3. This issue started occurring after I switched to a new monitor. My previous monitor also used a DP-to-DP connection and worked perfectly.

I am using deeveedee latest oc1.0.6-efi-r01.zip. Currently, when connected via DP, the screen experiences random black screens and flickering. If I use HDMI, the monitor fails to wake after sleep.

How should I patch my files to fix the DP connection?

[Asural]

On 12/31/2025 at 8:23 AM, cass said:

Hello everyone,

I have an HP 800 G4 DM (i5-8500, UHD 630) running macOS Sequoia 15.7.3. This issue started occurring after I switched to a new monitor. My previous monitor also used a DP-to-DP connection and worked perfectly.

I am using deeveedee latest oc1.0.6-efi-r01.zip. Currently, when connected via DP, the screen experiences random black screens and flickering. If I use HDMI, the monitor fails to wake after sleep.

How should I patch my files to fix the DP connection?

 

First, use @deeveedee's settings as is, and then:
1. Add force-online = <01000000>
2. Add igfxfw = <02000000>

 

For DP to DP, try setting framebuffer-con0-busid = <05000000> to check if it works.
As for DP to DP, I think you're using a high-performance monitor, but replacing the DP cable with a DP2.0 cable should fix the problem.
 

There should be a guide on the forums, but please refer to this guide.
 

EDIT:

I find it difficult to judge @deeveedee's recipe.
Fortunately, she has provided an explanation herself, so please ask questions, including details about the monitor you are using.
 

 

Edited January 15 by Asural

[verdazil]

Asural's suggestion is correct. Replacing the cable can indeed fix the issue, but not because it is a higher DP2.0 standard (Intel UHD 630 does not support DP2.0 anyway).
It helps only if the new cable is of clearly better quality and provides a more stable signal. The actual DP standard of the cable is not important. It is also clear that by default DP2.0 cables are of higher quality than DP

Edited January 14 by verdazil

[deeveedee]

@cass If those suggestions don't fix your issues, please re-read the instructions.  The DeviceProperties that I provide in oc1.0.6-efi-r01.zip are specifically for my hack which uses 3 DP->DVI-D adapters (my 3 displays are Dell displays with DVI-D inputs).  If you are using DP->DP (no adapters) the instructions indicate that you may need to change your graphics DeviceProperties.  The instructions have links to sample DeviceProperties that may work better for you.

 

EDIT: @Asural oc1.0.6-efi-r01.zip specifies boot-args igfxfw=2 and igfxonln=1 instead of the DeviceProperties.

 

EDIT2: @cass With regard to sleep/wake, see this.  You may need to remove boot-arg darkwake=2.

Edited January 14 by deeveedee

[deeveedee]

@cass If you still haven't fixed your display issues, you may want to refer to these threads:

• UHD 630 missing 5120x1440
• HP EliteDesk 800 G5 DM with Philips 34M2C8600

[Asural]

13 hours ago, deeveedee said:

@cass If you still haven't fixed your display issues, you may want to refer to these threads:

• UHD 630 missing 5120x1440
• HP EliteDesk 800 G5 DM with Philips 34M2C8600

 

The solution will vary depending on the type of monitor.
I'll edit this post and leave the rest to you.