Skip to content

Framebuffer_Patching

Directory actions

More options

Directory actions

More options

Latest commit

 

History

History

Framebuffer_Patching

README.md

Intel iGPU Framebuffer patching for external displays (Laptop)

TABLE of CONTENTS (click to reveal)

TABLE of CONTENTS

About

This guide is for modifying DeviceProperties for connector types Intel iGPUs, so you can connect a secondary display to the HDMI or DisplayPort of your Laptop.

Problem description

Your Laptop boots into macOS and the internal screen works, but:

  1. if you connect a secondary monitor to your Laptop it won't turn on at all or
  2. the handshake between the system and both displays takes a long time and both screens turn off and on several times during the handshake until a stable connection is established.

Note

If you don't get a picture at all you could try a fake ig-platform-id to force the system into VESA mode. For desktop systems, try CaseyJ's General Framebuffer Patching guide instead.

Possible causes

  • Using an incorrect or sub-optimal AAPL,ig-platform-id for your iGPU
  • Misconfigured framebuffer patch with incorrect BusID and/or flags for the used cable/connector

Solution

  • Adjust the framebuffer patch for your iGPU

Supported Connection Types

  • HDMI → HDMI
  • DP → DP (DisplayPort)
  • HDMI → DVI
  • DP → DVI
  • VGA (Skylake and newer only)

Note

  • 💡 Although the examples used throughout this guide are for getting the Intel UHD 620 to work, the basic principle is applicable to any other iGPU model supported by macOS as well. Just make sure to use the framebuffer data required for your iGPU.
  • VGA supposedly works out of the box on Skylake and newer but since I have no machine to test this you are on your own in this case. Disabling ADGC via device properties seems to be required as well.

Workflow overview

This it the tl;dr version of what we are going to do basically:

  1. Copy working EFI to FAT32 formatted USB flash drive
  2. Find a suitable Framebuffer
    • Find your iGPU
    • Add recommended AAPL,ig-platform-id to DeviceProperties
    • Add default Connector Data to config.plist
  3. Test if ext. Monitor is working
  4. Adjust/modify connector data to optimize handshake
  5. Test again
  6. Repeat steps 4 and 5 until you think it's optimal
  7. Add framebuffer patch to the config.plist on system disk.

1. Preparations

Create a bootable USB flash drive

  • Mount your system's EFI partition
  • Copy your EFI folder to a FAT32 formatted USB flash drive
  • Unmount the EFI partition again – from now on, We will work with the config stored on the USB flash drive!
  • Reboot
  • Change the boot order of your drives in the BIOS so that the USB flash drives takes the first slot. Otherwise you have to select the USB flash drive manually after each reboot

Explanation: Since we will probably have to do a lot of rebooting to test the framebuffer, we will not work with the config.plist stored on the internal disk because a) we don't want to mess up our working configuration and b) we don't have mount the EFI partition every time to access the config.plist since it's stored on a flash drive. This really speeds up the workflow.

Required Tools and Resources

  • A FAT32 formatted USB Flash drive
  • External Display and cable(s) to populate the output(s) of your mainboard (usually HDMI an/or DisplayPort)
  • Lilu and Whatevergreen kexts enabled (mandatory)
  • Hackintool App for creating/modifying framebuffer properties
  • ProperTree to copy over Device Properties to your config
  • Intel Ark (for researching CPU specs such as used on-board graphics and device-id)
  • OpenCore Install Guide (for referencing default/recommended framebuffers)
  • Intel HD Graphics FAQs for Framebuffers and Device-IDs and additional info.
  • Big to Little Endian Converter to convert Framebuffers from Big Endian to Little Endian and vice versa
  • Optional: OCToolbox – includes calculators for Freamebuffer and Connector flags (can also reverse checksums into the included flags)

2. Test your current configuration

Before we do any editing we will run a basic test. You can skip this if you already know that your external display isn't working. Observe what happens after attaching the external display to your Laptop:

Ext. Display turns On? Ext. Display detected
in Hackintool?		 Action(s)
No No
No Yes (Index?) Adjust flags for the connector detected at Index X (X= con1 or con2)

If the display is detected in Hackintool's "Patch" section, either Index 1 or Index 2 should turn red:

display-red

If the display is detected and turns on:

Ext. Display detected
in Hackintool?		 Handshake Symptoms Action
Yes (Index?) Slow
  • Mouse Cursor lagging
  • System feels unresponsive
  • Display turns on late after completing boot sequence
  • Displays turn on and off more than 3 times during handshake
 Adjust connector flags for the connector at detected Index. In my case it's connected via con2.
Yes (Index?) Fast Everything feels normal Congrats. Nothing to do!

Take note of your test results. Depending on the results you might be able to skip sections.

3. Verify/adjust the AAPL-ig-platform-id

  1. Find the CPU used in your Notebook. If you don't know, you can enter in Terminal:

    sysctl machdep.cpu.brand_string

  2. Search your model number on https://ark.intel.com/ to find its specs. In my case it's an i5-8265U.

  3. Take note of the the CPU family it belongs to (for example "Whisky Lake")

  4. Identify the iGPU model of the CPU. If the actual model of the iGPU is not specified (i.e. if it says "Intel® UHD Graphics for xth Generation Intel® Processors"), use sites like netbookcheck.net or check in Windows Device Manager to find the exact model. In my case, it's an Intel UHD Graphics 620:
    devmanigp

  5. Next, verify that you are using the recommended AAPL,ig-platform-id for your CPU and iGPU:

    • Find the recommended framebuffer for your mobile CPU family in this list (based on data from the OpenCore Install Guide)
    • Check if your iGPU requires a device-id to spoof a different iGPU model!
    • Compare the data with the DeviceProperties used in your config.plist

  6. Make sure to cross-reference the default/recommended framebuffer for your iGPU against the ones listed in the Intel HD Graphics FAQs. But keep in mind that the Intel HD FAQs uses Big Endian instead of Little Endian which is required for the config.plist.

  7. If necessary, adjust the framebuffer patch (mainly AAPL,ig-platform-id) in the config.plist stored on your USB flash drive according to the data you gathered in steps 4 or 5. If you are already using the correct/recommended AAPL,ig-platform-id, then you can skip to the next chapter "Adding Connectors".

  8. If you have to change the AAPL,ig-platform-id but your framebuffer patch already contains connector patches (entries containing framebuffer-con…), disable the whole device property entry by placing # in front of the dictionary #PciRoot(0x0)/Pci(0x2,0x0) and create a new one: PciRoot(0x0)/Pci(0x2,0x0) to start with a clean slate.

  9. Add the recommended data you found. If your system requires additional properties so that the internal display works correctly (like backlight register fixes, etc.), copy them over from your previous framebuffer patch.

  10. Save your config and reboot from the USB flash drive. If the system boots and the internal display works, we can now add data to connect to an external display. If it doesn't boot, reset the system, boot from the internal disk and start over.

Note

  • The OpenCore Install Guide only provides basic settings to enable your primary display. It does not include additional connectors (except for Ivy Bridge Laptops).
  • In my case, the recommended framebuffer and device-id for the Intel UHD 620 differ: Dortania recommends AAPL,ig-platform-id 00009B3E and device-id 9B3E0000 to spoof the iGPU as Intel UHD 630, while Intel HD FAQs recommends AAPL,ig-platform-id 0900A53E and device-id A53E0000 to spoof it as Intel Iris 655 which worked better for me in the end.
  • To resolve issues with HDMI handshake, you need to disable Apple Graphics Device Control (AGDC) as it can cause conflicts when using a spoofed spoofing SMBIOS/Board-ID with non-native macOS versions!

4. Understanding the Parameters

Let's have a look inside Hackintool's "Connectors" tab to understand the parameters we are working with:

Parameter Description
Index An Index represents a physical graphics output on your Laptop. In macOS, up to 3 software connectors can be assigned (con0 to con2) to 3 connectors (Indexes 1 to 3). Index -1 has no physical connector:
Connectors
Framebuffers which only contain -1 Indexes (often referred to as "headless" or "empty") are used in setups where a discrete GPU is used for displaying graphics while the iGPU performs computational tasks only, e.g. Platform-ID 0x9BC80003:
headless
BusID
The Bus ID is used to select the busses or pathways available for connecting displays. Every connector (con) must be assigned a unique BusID through which the signal travels from the iGPU to the physical port(s). Unique means each Bus ID can only be assigned to one connector at a time! And: only certain combinations of BusIDs and connector Types are allowed:
  • For DisplayPort: 0x02, 0x04, 0x05 or 0x06
  • For HDMI: 0x01, 0x02, 0x04, 0x06 (availabilty may vary)
  • For DVI: same as HDMI
  • For VGA: N/A
Pipe Responsible for taking the graphics data from the iGPU and converting it into a format that can be displayed on a monitor or screen. It performs tasks such as scaling, color correction, and synchronization to ensure that the visual output appears correctly on the connected display. This is fixed for each framebuffer
Type Type of the physical connector (DP, HDMI, DVi, LVDS, etc). Each connector type has a specific value associated with it:
  • DP: 00040000
  • HDMI: 00080000
  • DVI: 00800000
⚠️ When using cables that have different connectors on each end (i.e. DisplayPort > DVI, etc.), you must use HDMI as connector type!
Flags A bitmask representing connector "Flags" for the selected connector. The recommended value for connect value for any connection is C7030000:
Flags
For a complete list of framebuffer and connector flags, click here

Understanding the framebuffer-conX-alldata property

This is special property which allows to patch multiple connectors in sequence by putting them in a single string and specifying the index of a connector to start with. The string length should be a multiple of 12 bytes (the length of a single connector), 24 bytes for ICL. In other words, the con-alldate patch injects Index, BusID, Pipe, Type and Flags for numerous connectors in one go.

An example for the usage of this method of custom patching can be found in the framebuffer patch for Ivy Bridge Laptops with Intel HD 4000 graphics and a display panel with 1600x900 px or more which using AAPL,ig-platform-id 0x0166000, which only has one connector for the internal display:

ID: 01660004, STOLEN: 32 MB, FBMEM: 16 MB, VRAM: 1536 MB, Flags: 0x00000000
TOTAL STOLEN: 16 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 16 MB, MAX OVERALL: 17 MB (18354176 bytes)
Camellia: CamelliaUnsupported (255), Freq: 1808 Hz, FreqMax: 1808 Hz
Mobile: 1, PipeCount: 3, PortCount: 1, FBMemoryCount: 1
[5] busId: 0x03, pipe: 0, type: 0x00000002, flags: 0x00000230 - ConnectorLVDS
05030000 02000000 30020000

To inject additional connectors, the ones from 0x01660003 (which is for standard def displays) can be used which contains the following connectors:

02050000 00040000 07040000
03040000 00040000 81000000
04060000 00040000 81000000

This results in the following string for con1-alldata:

framebuffer-con1-alldata: 02050000 00040000 07040000 03040000 00040000 81000000 04060000 00040000 81000000

Understanding the framebuffer-unifiedmem property

This device property can be used to allocate more RAM to the iGPU as VRAM. On laptops, the default usually is 1536 MB. With the framebuffer-unifiedmem property, you can increase the amount of VRAM to address graphical glitches or artifacts. On my Lenovo T530 for example, the scrollbar in Firefox becomes glitchy (pink horizontal stripes) if only 1536 MB of VRAM are allocated. Increasing the amount of VRAM to 2048 MB fixes this issue.

Below you find the hex values to allocate x MB of VRAM:

HEX value Allocated VRAM
00000040 1024 MB
00000060 1536 MB
00000080 2048 MB
000000A0 2560 MB
000000C0 3072 MB
000000E0 3584 MB
FFFFFFFF 4096 MB

Important

  • According to the Whatevergreen FAQ, using the framebuffer-unifiedmem property is not recommended (but no explanation is provided).
  • This should be obvious: don't assign more VRAM than physical RAM is installed in your system!
  • Disable/delete the framebuffer-stolenmem property if you want to increase the amount of VRAM which is handled by framebuffer-unifiedmem. Properties stolenmen and unifiedmem should not be used together at the same time!

5. Adding Connectors

Manual Method (click to reveal)

Adding Connectors (Manual Method)

Now that we have verified that we are using the recommended framebuffer, we need to gather the connectors data associated with the selected framebuffer in the Intel HD FAQs. Since there are 2 different recommendations for my iGPU, I will look at both.

Gather data for your framebuffer (Example 1)

The recommended Framebuffer for my Intel UHD suggested by Dortania is AAPL,ig-platform-id 00009B3E. Now we need to find the connector data for this framebuffer in the Intel HD FAQs:

  1. Convert the value for framebuffer to Big Endian. You can use Hackintool's calculator to do this. In my case it's 0x3E9B0000.
  2. Visit the Intel HD Graphics FAQs
  3. Press CMD+F to search within the site
  4. Enter your framebuffer (converted to Big Endian, without the leading 0x), here: 3E9B0000
  5. You should find your value in a table with other framebuffers
  6. Scroll down past the table until you see "Spoiler: … connectors". Click on it to reveal the data
  7. Hit forward in the search function to find the next match. This will be the framebuffer data for your AAPL,ig-platform-id!

This is the Data for ID 3E9B0000:

ID: 3E9B0000, STOLEN: 57 MB, FBMEM: 0 bytes, VRAM: 1536 MB, Flags: 0x0000130B
TOTAL STOLEN: 58 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 172 MB, MAX OVERALL: 173 MB (181940224 bytes)
Model name: Intel HD Graphics CFL CRB
Camellia: CamelliaDisabled (0), Freq: 0 Hz, FreqMax: 0 Hz
Mobile: 1, PipeCount: 3, PortCount: 3, FBMemoryCount: 3

[0] busId: 0x00, pipe: 8, type: 0x00000002, flags: 0x00000098 - ConnectorLVDS
[1] busId: 0x05, pipe: 9, type: 0x00000400, flags: 0x00000187 - ConnectorDP
[2] busId: 0x04, pipe: 10, type: 0x00000400, flags: 0x00000187 - ConnectorDP

00000800 02000000 98000000
01050900 00040000 87010000
02040A00 00040000 87010000

The picture below lists the same data for the 3 connectors this framebuffer provides but with some additional color coding:

FBADATA02

More Examples (click to reveal)

Gather data for your framebuffer (Example 2)

Since the Intel HD FAQs recommends a different framebuffer in certain cases you should double-check this, too. So look-up the data for your CPU family in the document and scroll down to where it says "Recommended framebuffers". In my case the Intel HD FAQs suggests 0x3EA50009 instead.

Here's the Data for ID: 3E9B0000

ID: 3EA50009, STOLEN: 57 MB, FBMEM: 0 bytes, VRAM: 1536 MB, Flags: 0x00830B0A
TOTAL STOLEN: 58 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 172 MB, MAX OVERALL: 173 MB (181940224 bytes)
Model name: Intel HD Graphics CFL CRB
Camellia: CamelliaV3 (3), Freq: 0 Hz, FreqMax: 0 Hz
Mobile: 1, PipeCount: 3, PortCount: 3, FBMemoryCount: 3

[0] busId: 0x00, pipe: 8, type: 0x00000002, flags: 0x00000098 - ConnectorLVDS
[1] busId: 0x05, pipe: 9, type: 0x00000400, flags: 0x000001C7 - ConnectorDP
[2] busId: 0x04, pipe: 10, type: 0x00000400, flags: 0x000001C7 - ConnectorDP

00000800 02000000 98000000
01050900 00040000 C7010000
02040A00 00040000 C7010000

Gathering data for your framebuffer (Example 3)

In the end, I settled with framebuffer 0x3EA50004 instead and in the end you will understand why.

ID: 3EA50004, STOLEN: 57 MB, FBMEM: 0 bytes, VRAM: 1536 MB, Flags: 0x00E30B0A
TOTAL STOLEN: 58 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 172 MB, MAX OVERALL: 173 MB (181940224 bytes)
Model name: Intel Iris Plus Graphics 655
Camellia: CamelliaV3 (3), Freq: 0 Hz, FreqMax: 0 Hz
Mobile: 1, PipeCount: 3, PortCount: 3, FBMemoryCount: 3

[0] busId: 0x00, pipe: 8, type: 0x00000002, flags: 0x00000498 - ConnectorLVDS
[1] busId: 0x05, pipe: 9, type: 0x00000400, flags: 0x000003C7 - ConnectorDP
[2] busId: 0x04, pipe: 10, type: 0x00000400, flags: 0x000003C7 - ConnectorDP

00000800 02000000 98040000
01050900 00040000 C7030000
02040A00 00040000 C7030000

Next, we need to "translate" this data into DeviceProperties for our config.plist so we can inject it into macOS. But before we do we should look at what all of these parameters mean…

Understanding the Parameters

Let's have a look inside Hackintool's "Connectors" tab to get to know the parameters we are working with:

Parameter Description
Index An Index represents a physical graphics output on your Laptop. In macOS, up to 3 software connectors can be assigned (con0 to con2) to 3 connectors (Indexes 1 to 3). Index -1 has no physical connector:
Connectors
Framebuffers which only contain -1 Indexes (often referred to as "headless" or "empty") are used in setups where a discrete GPU is used for displaying graphics while the iGPU performs computational tasks only, such as Platform-ID 0x9BC80003:
headless
BusID
The Bus ID is used to select the busses or pathways available for connecting displays. Every connector (con) must be assigned a unique BusID through which the signal travels from the iGPU to the physical port(s). Unique means each Bus ID can only be assigned to one connector at a time! And: only certain combinations of BusIDs and connector Types are allowed:
  • For DisplayPort: 0x02, 0x04, 0x05 or 0x06
  • For HDMI: 0x01, 0x02, 0x04, 0x06 (availability may vary)
  • For DVI: same as HDMI
  • For VGA: N/A
Pipe Responsible for taking the graphics data from the iGPU and converting it into a format that can be displayed on a monitor or screen. It performs tasks such as scaling, color correction, and synchronization to ensure that the visual output appears correctly on the connected display. This is fixed for each framebuffer
Type Type of the physical connector (DP, HDMI, DVi, LVDS, etc). Each connector type has a specific value associated with it:
  • DP: 00040000
  • HDMI: 00080000
  • DVI: 0080000
Flags A bitmask representing connector "Flags" for the selected connector. The recommended value for connect value for any connection is C7030000:
Flags
For a complete list of framebuffer and connector flags, click here

Translating the data into DeviceProperties

Recap: here is the suitable framebuffer patch we found earlier:

ID: 3E9B0000, STOLEN: 57 MB, FBMEM: 0 bytes, VRAM: 1536 MB, Flags: 0x0000130B
TOTAL STOLEN: 58 MB, TOTAL CURSOR: 1 MB (1572864 bytes), MAX STOLEN: 172 MB, MAX OVERALL: 173 MB (181940224 bytes)
Model name: Intel HD Graphics CFL CRB
Camellia: CamelliaDisabled (0), Freq: 0 Hz, FreqMax: 0 Hz
Mobile: 1, PipeCount: 3, PortCount: 3, FBMemoryCount: 3

[0] busId: 0x00, pipe: 8, type: 0x00000002, flags: 0x00000098 - ConnectorLVDS
[1] busId: 0x05, pipe: 9, type: 0x00000400, flags: 0x00000187 - ConnectorDP
[2] busId: 0x04, pipe: 10, type: 0x00000400, flags: 0x00000187 - ConnectorDP

00000800 02000000 98000000
01050900 00040000 87010000
02040A00 00040000 87010000

No we need to to "translate" this into DeviceProperties

Address: PciRoot(0x0)/Pci(0x2,0x0)

You probably have these entries already – just with the values recommended for your iGPU:

Key Type Value Notes
AAPL,ig-platform-id Data 00009B3E For Laptops with UHD 620
framebuffer-patch-enable Data 01000000 Enables Framebuffer patching via Whatevergreen
framebuffer-stolenmem Data 00003001 Only needed if "About this Mac" section shows 7mb or less after patching
framebuffer-fbmem Data 00009000 Only needed if "About this Mac" section shows 7mb or less after patching
device-id Data 9B3E0000 Device-ID is required for UHD 620

And these we need for the Connectors:

For now, we will leave every value as is, except connector type, since most modern systems use HDMI instead of DisplayPort.

Key Type Value Notes
AAPL,slot-name String Internal@0,2,0 Internal location of the iGPU (optional). This lists the iGPU in the "Graphics" category of System Profiler
device-id Data 9B3E0000 For spoofing Intel UHD 620 as Intel UHD 630. Only add if required for your iGPU model.
device_type String VGA compatible controller Optional. If you are installing macOS on a legacy system which doesn't have drivers for your iGPU, you should disable it so the display can run in VESA mode. Otherwise it might just turn off.
disable-external-gpu Data 01000000 Optional. Only required if your Laptop has an incompatible dGPU
framebuffer-con1-busid Data 05000000  BusID used to transmit data to the physical port # 1 on your machine
framebuffer-con1-enable Data 01000000 Enables Patching Connector #2 via Whatevergreen
framebuffer-con1-flags Data 87010000 Default flags for connector 3
framebuffer-con1-index Data 01000000 Connector 3 has Index 2
framebuffer-con1-pipe Data 09000000 Pipe 9
framebuffer-con1-type Data 00080000 HDMI. If you have DisplayPort use 00040000 instead
framebuffer-con2-busid Data 04000000  BusID used to transmit data to physical port #2 of your machine
framebuffer-con2-enable Data 01000000 Enables Patching Connector #3 via Whatevergreen
framebuffer-con2-flags Data 87010000 Default flags for connector 3
framebuffer-con2-index Data 02000000 Connector 3 has Index 2
framebuffer-con2-pipe Data 0A000000 Pipe 10, converted to hex = 0A
framebuffer-con2-type Data 00080000 HDMI. If you have DisplayPort use 00040000 instead
framebuffer-con3-busid Data 00000000  BusID used to transmit data to physical port #2 of your machine
framebuffer-con3-enable Data 01000000 Optional. Enables Patching Connector #4 via Whatevergreen
framebuffer-con3-index Data FFFFFFFF Optional. Disables the dummy con3
framebuffer-con3-pipe Data 00000000 Optional. Selects Pipe 0 which takes con3 offline
framebuffer-patch-enable Data 0100000 Enables Framebuffer patching via Whatevergreen
model String Intel UHD Graphics 620 Optional property

Optional Properties:

Key Type Value Notes
enable-backlight-registers-fix Data 01000000 Fixes backlight registers on Kaby Lake, Coffee Lake and Ice Lake platforms. Add this if your internal screen turns black during booting
enable-backlight-registers-alternative-fix Data 01000000 Same but for macOS 13.4+

[!NOTE] We don't add properties for con0 since this is the internal display which should work fine with the correct framebuffer.

This is how the DeviceProperties for your iGPU should look like now:

cfg-step1

Semi-automated method using Hackintool (click to reveal)

Semi-automated method using Hackintool

Generating a framebuffer patch with Hackintool

  1. Run Hackintool
  2. In the menu bar, choose the "Framebuffer" type. Select either ≤ macOS 10.13 (High Sierra and older) or ≥ macOS 10.14 (Mojave and newer, default):
    Menubar
  3. Next, click on "Patch".
  4. Then click on "Connectors"
  5. From the "Intel Generation" dropdown menu, select the CPU family your CPU belongs to. Since my Whiskey Lake CPU is 8th Gen and since 8th and 9th gen Intel CPUs belong to the Coffee Lake family, I select Coffee Lake)
  6. Next, specify the "Platform ID" to use. For this example, I am using the recommended framebuffer by Dortania, 0x9B3E0000:
    start01
  7. The list below the "Connectors" tab shows the default configuration of the selected Framebuffer:
    start02
  8. Leave Index 0 (= internal display) and Index 1 untouched!
  9. If you are using HDMI to HDMI or HDMI to DVI, change the "Type" for Index 1 and Index 2 to HDMI:
    cons01
  10. Next, we modify the connector "Flags" for Index 1 and Index 2:
    cons02
  11. We want the sum to be 0x000003C7, which consists of the following flags:
    • CNAlterAppertureRequirements
    • CNUnknownFlag_2
    • CNUnknownFlag_4
    • CNDisableBlitTranslationTable
    • CNUnknownFlag_80
    • CNUnknownFlag_100
  12. Next, click on "Patch".
  13. In the "General" section, enable the following settings:
    patch01
  14. Next, click the "Advanced" tab, select the following settings (and read the notes):
    patch02
  15. Next, click on "LSPCON" and read the text that appears when hovering over the "Enable Driver" box. If you have verified that your iGPU supports HDMI 2.0 and is routed via the iGPU you can enable the driver and select the "Preferred Mode". If uncertain, just leave it on "Auto Detect":
    patch03
  16. Now, click on "Generate Patch" located at the bottom of the window. The empty black area will be filled with the raw text for a .plist containing the DeviceProperties for your iGPU:
    generate01
  17. Click in the text area. Press CMD+A to select the text, press CMD+C to copy it to the clipboard
  18. Run ProperTree
  19. Press CMD+V and you should have something like this:
    result01
  20. Now, you could add the dictionary PciRoot(0x0)/Pci(0x2,0x0) to your config.plist as is, but there are some entries in there that we don't need, so do the following:
    • Delete all framebuffer-con0- properties since they are the default settings for the internal screen
    • Delete all entries for framebuffer-con3- since this is for the dummy connector which is not used anyway.
    • Change the value for model by entering the name of your actual iGPU, like Intel UHD Graphics 620 in my case.
    • Disable/delete framebuffer-stolenmem if you want to use 2048 MB of VRAM which is handled by framebuffer-unifiedmem. stolenmen and unifiedmem should not be used at the same time.
    • Add additional properties required for your iGPU (check Whatevergreen repo for details). In my case I need a backlight registers fix for Kaby Lake and newer which is property enable-backlight-registers-fix or enable-backlight-registers-alternative-fix (macOS 13.4+)
  21. After editing, the framebuffer patch might look like this:
    result02
  22. Now copy the dictionary PciRoot(0x0)/Pci(0x2,0x0) to the clipboard, open your config.plist on your USB flash drive and replace the existing entry under DeviceProperties/Add

Optional Properties:

Key Type Value Notes
enable-backlight-registers-fix Data 01000000 Fixes backlight registers on Kaby Lake, Coffee Lake and Ice Lake platforms. Add this if your internal screen turns black during booting
enable-backlight-registers-alternative-fix Data 01000000 Same but for macOS 13.4+

6. Testing and modifying the framebuffer patch

Now that we have added the default connectors for the selected framebuffer reboot from your USB flash drive and connect your external monitor.

⚠️ If you are using any kind of SMBIOS/board-id and/or device-id spoof, add the following key to your Framebuffer Patch:

Key Type Value
disable-agdc DATA 01000000

It disables Apple Graphics Device Control (AGDC) since it’s known to cause issues during the handshake between the HDMI port and external displays. If you are lucky, this might be the only thing you have to change. Save your config.plist and reboot.

Observe the behavior of the system when connecting an external display:

Case Ext. Display
ON?		 Detected in
Hackintool		 Handshake Action
1 NO NO – Change the BusIDs for con1 and con2 and test again
2 NO YES – Take note of the Index and BusID and adjust the connector flags and test again
3 YES YES Slow Modify connector flags and test again
4 YES YES Fast You're done. Transfer the DeviceProperties to your main config.plist

If case 1 occurs

Since the external display has not been detected yet, it's most likely that the BusIDs for both connectors is incorrect. And since we don't know which connector is actually used we need to change the Bus ID for both.

  • Possible BusIDs are: 1, 2, 4, 5, or 6
  • The same BusID can only be used for one con at a time!
  • Listed below you find all possible unique combinations of connectors and BusIDs.
  • If you are lucky, you don't need to run all the tests until the monitor is detected and/or turns on!

Original values

Key Type Value
framebuffer-con1-busid Data 05000000
framebuffer-con2-busid Data 04000000

Next test

Change the BusIDs for each con, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 01000000  5
framebuffer-con2-busid Data 02000000 4

Next test

Change the BusIDs for each con, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 02000000  5, 1
framebuffer-con2-busid Data 01000000 4, 2

Next test

Change the BusIDs for each con, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 04000000  5, 1, 2
framebuffer-con2-busid Data 06000000 4, 2, 1

Next test

Change the BusIDs for each con, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 06000000  5, 1, 2, 4
framebuffer-con2-busid Data 05000000 4, 2, 1, 6

If the external display still won't be detected, there must be another issue. Check AAPL,ig-platform-id again.

If case 2 occurs

The testing procedure is the same as for case one. But you only have to test the BusIDs for con1 or con2 (depending on which con is detected). In this example, the external display has been detected on con1

Original values

Key Type Value
framebuffer-con1-busid Data 05000000
framebuffer-con2-busid Data 04000000

Next test

Change the BusIDs for the con that your monitor is using, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 01000000  5

Next test

Change the BusIDs for the con that your monitor is using, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 02000000  5, 1,

Next test

Change the BusIDs for the con that your monitor is using, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 04000000 5, 1, 2,
framebuffer-con2-busid Data 05000000 Needs to be changed once as well to avoid using the same BusID for both connectors twice (because the default BusID is 4 for con2)

Next test

Change the BusIDs for the con that your monitor is using, save the config.plist and reboot from USB flash drive.

Key Type Value Tested
BusIDs
framebuffer-con1-busid Data 06000000 5, 1, 2, 4

If the external display still won't be detected, there must be another issue. Check AAPL,ig-platform-id again.

If case 3 occurs

Modify the connector flags for the connector(s):

Key Type Value Tested
BusIDs
framebuffer-con1-flags Data C7030000 Works well when using HDMI to HDMI and HDMI to DVI
framebuffer-con2-flags Data C7030000 Works well when using HDMI to HDMI and HDMI to DVI

Safe your config.plist, reboot from USB flash drive and observe if the handshake improves now. When using Adapters like HDMI to DVI the handshake takes a bit longer than using HDMI to HDMI but it should improve nonetheless.

If case 4 occurs

Congratulations. Continue with step 7.

7. Final Steps

Once you've found a framebuffer patch you are happy with, do the following:

  • Open the config.plist containing your framebuffer patch with ProperTree
  • Copy the Dictionary PciRoot(0x0)/Pci(0x2,0x0) to the clipboard (CMD+c)
  • Mount your system's EFI
  • Open your config.plist with ProperTree
  • Go to DeviceProperties/Add
  • Delete Dictionary PciRoot(0x0)/Pci(0x2,0x0)
  • Press CMD+v to paste the new framebuffer patch
  • Save and reboot
  • In BIOS, change the boot order, so that the internal disk takes the firs slot again.
  • Save and exit
  • Boot macOS from internal drive
  • Done

Note

  • You don't need to inject a property for a con, if the injected parameter is the same as the default used by the selected framebuffer already!
  • Besides connector flags there are also framebuffer flags to experiment with.
  • Look into Intel HD FAQs for better suited framebuffer patches than the ones recommended by Dortania! For the UHD 620 on Laptops for example, 0x3EA50004 is suited much better than the one recommended by Dortania since it already uses the required flags by default.

Credits and further resources