Embedded Controller (EC)

Embedded Controller (EC)

Starting in macOS 10.15 (Catalina), macOS now stalls when booting and attaching to an EC with the device id of "PNP0C09" and is not named EC within the ACPI tables. This normally manifests itself as messages similar to apfs_module_start... or waiting for root device when attempting to boot. With a desktop, we would normally just put in a fake embedded controller with the correct properties and call it a day - but for laptops we rename the existing embedded controller in order to get battery status working. The general gist is that:

  1. You need to dump your DSDT
  2. Decompile said DSDT
  3. Figure out which EC is the main one in your DSDT
  4. Put in the right rename into the patches section of your Config.plist

For more info, you can read this guide, also by Hackintosh Slav. This page is more or less a copy and paste from the laptop page specifically.

Dumping the DSDT

MaciASL

  • When you open MaciASL, it should open directly to your system's DSDT. If it does not, you can go into the top left corner and hit "File" -> "New from ACPI" -> "DSDT". What you are seeing is the decompiled form of your DSDT, so you can skip ahead to figuring out which EC you need.
  • This needs to be done on the target computer, and if you have any ACPI fixes or patches applied from Clover or OpenCore, those will be applied to the DSDT you see in MaciASL.

SSDTTime

  • Can be ran on either Windows or Linux
  • If you don't have an internet connection on that device, or are using Python 2 (or iasl otherwise fails to download) you may need to download iASL and put it in the scripts folder.

acpidump.exe

  • In command prompt run path/to/acpidump.exe -b -n DSDT -z, this will dump your DSDT as a .dat file. Rename this to DSDT.aml

Pressing F4 in Clover

  • This dumps your DSDT in EFI/CLOVER/ACPI/origin. This folder must exist bfeore you dump though.

acpidump.efi

  • Add this to EFI/OC/Tools and in your config under Misc -> Tools with the argument: -b -n DSDT -z. Select this option in OpenCore's picker, then rename DSDT.dat to DSDT.aml.
  • If OpenCore is having issues running acpidump, you can call it from the shell with OpenShell, which is bundled within OpenCorePkg (reminder to add to both EFI/OC/Tools and in your config under Misc -> Tools):
shell> fs0: // replace with proper drive

fs0:\> dir // to verify this is the right directory

Directory of fs0:\

01/01/01 3:30p EFI

fs0:\> cd EFI\OC\Tools // note that it's with forward slashes

fs0:\EFI\OC\Tools> acpidump.efi -b -n DSDT

Decompiling the DSDT

So once we have our DSDT we still got a bit of work left, we'll first want to decompile it so we can view it easier. Couple options:

macOS

So decompiling DSDTs is quite easy with macOS, all you need is MaciASL. To decompile, just open the file!

Windows

Decompiling on windows is fairly simple as well, you will need iasl.exe and Command Prompt:

path/to/iasl.exe path/to/DSDT.aml

Linux

Compiling and decompiling with Linux is just as simple, you will need a special copy of iasl and terminal:

path/to/iasl path/to/DSDT.aml

Finding the right EC patch

Now that our DSDT is readable, next search for PNP0C09. Should give you something similar to this:

As you can see our PNP0C09 is found within the Device (EC0) meaning this is the device we want to rename.

What happens if multiple PNP0C09 show up

When this happens you need to figure out which is the main and which is not, it's fairly easy to figure out. Check each controller for the following properties:

  • _HID
  • _CRS
  • _GPE

Note that only the main EC needs renaming, if you only have one PNP0C09 then it is automatically your main regardless of properties.

Applying your EC patch

As you can see from the table below, we'll be renaming our EC listed in the DSDT. Do note you cannot just throw random renames without checking first, as this can cause actual damage to your laptop.

Comment Find*[HEX] Replace[HEX]
change EC0 to EC 4543305f 45435f5f
change H_EC to EC 485f4543 45435f5f
change ECDV to EC 45434456 45435f5f
change PGEC to EC 50474543 45435f5f

Add the rename as shown below:

Comment Type Change XXXX to EC
Enabled Boolean YES
Count Number 0
Limit Nuber 0
Find Data xxxxxxxx
Replace Data xxxxxxxx

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