krackers · August 8, 2024 22:05 · Nov 16, 2020 · Jun 18, 2020 · Jun 18, 2020 · Jun 18, 2020
diff --git a/patch-edid.md b/patch-edid.md
@@ -1,53 +1,40 @@
 ## patch-edid.rb
 
-A script to fix EDID problems on external monitors in Mac OS.
+A script to fix EDID problems on external monitors in macOS.
 
-### Additional reading
-
-* [The original forum thread](http://embdev.net/topic/284710)
-* An improved version of the script [by adaugherity](https://gist.github.com/adaugherity/7435890)
-* [An explaination of the problem](https://spin.atomicobject.com/2018/08/24/macbook-pro-external-monitor-display-problem/) from Atomic Object's blog
 
 ### Instructions
 
-⚠️ **This requires disabling SIP, so run this at your own risk. Be sure to re-enable SIP at the end.**
+1. Connect only the problem display.
 
-1. Disable [System Integrity Protection](https://support.apple.com/en-us/HT204899) while in [Recovery Mode](https://support.apple.com/en-us/HT201314). Reboot back into macOS when done.
+1. Create this directory structure (if it doesn't already exist):
 
-    ```
-    csrutil disable
+    ```shell
+    sudo mkdir -p /Library/Displays/Contents/Resources/Overrides
     ```
 
-1. For macOS Catalina and newer (which uses a [read-only system volume](https://support.apple.com/en-us/HT210650)), mount the system drive read/write (yes, this is in addition to disabling SIP)
+1. Download this ruby script in that directory:
 
-    ```
-    sudo mount -uw /
-    ```
-
-1. Connect *only* the problem monitor
-
-1. Download this script in the directory containing all the display override plist files (note: even with the steps above, this command requires sudo to run):
-
-    ```
-    cd /System/Library/Displays/Contents/Resources/Overrides
+    ```shell
+    cd /Library/Displays/Contents/Resources/Overrides
     sudo curl -O https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
     ```
 
-    You may also want to use [adaugherity's version](https://gist.github.com/adaugherity/7435890) of the script:
+    *Note: You may want to use [adaugherity's version](https://gist.github.com/adaugherity/7435890) of the script instead.*
 
-    ```
-    cd /System/Library/Displays/Contents/Resources/Overrides
-    sudo curl -O https://gist.github.com/adaugherity/7435890/raw/patch-edid.rb
-    ```
-
-1. Run the script we just downloaded (as root again). This creates a new display override plist.
+1. Run the script we just downloaded (as root again). This creates a new display override plist file.
 
-    ```
+    ```shell
+    cd /Library/Displays/Contents/Resources/Overrides
     sudo ruby patch-edid.rb
     ```
 
-1. Reboot into recovery mode to re-enable SIP.
+1. Unplug and replug in the problem display.
 
-    ```
-    csrutil enable
-    ```
+### Additional reading/acknowledgements
+
+* [The original forum thread](http://embdev.net/topic/284710)
+* An improved version of the script [by adaugherity](https://gist.github.com/adaugherity/7435890)
+* [An explaination of the problem](https://spin.atomicobject.com/2018/08/24/macbook-pro-external-monitor-display-problem/) from Atomic Object's blog
+* Thanks so much to @stackrainbow for [pointing out](https://gist.github.com/ejdyksen/8302862#gistcomment-3460110) that this can be done without disabling SIP.
+* This version appears to work in Catalina and Big Sur. See earlier revisions for what worked (with disabling SIP) in earlier versions of macOS, which require the override plist to be in a different directory.
diff --git a/README.md → patch-edid.md b/README.md → patch-edid.md
diff --git a/README.md b/README.md
@@ -2,6 +2,14 @@
 
 A script to fix EDID problems on external monitors in Mac OS.
 
+### Additional reading
+
+* [The original forum thread](http://embdev.net/topic/284710)
+* An improved version of the script [by adaugherity](https://gist.github.com/adaugherity/7435890)
+* [An explaination of the problem](https://spin.atomicobject.com/2018/08/24/macbook-pro-external-monitor-display-problem/) from Atomic Object's blog
+
+### Instructions
+
 ⚠️ **This requires disabling SIP, so run this at your own risk. Be sure to re-enable SIP at the end.**
 
 1. Disable [System Integrity Protection](https://support.apple.com/en-us/HT204899) while in [Recovery Mode](https://support.apple.com/en-us/HT201314). Reboot back into macOS when done.
@@ -25,6 +33,13 @@ A script to fix EDID problems on external monitors in Mac OS.
     sudo curl -O https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
     ```
 
+    You may also want to use [adaugherity's version](https://gist.github.com/adaugherity/7435890) of the script:
+
+    ```
+    cd /System/Library/Displays/Contents/Resources/Overrides
+    sudo curl -O https://gist.github.com/adaugherity/7435890/raw/patch-edid.rb
+    ```
+
 1. Run the script we just downloaded (as root again). This creates a new display override plist.
 
     ```
@@ -36,5 +51,3 @@ A script to fix EDID problems on external monitors in Mac OS.
     ```
     csrutil enable
     ```
-
-Source: http://embdev.net/topic/284710
diff --git a/README.md b/README.md
@@ -4,7 +4,7 @@ A script to fix EDID problems on external monitors in Mac OS.
 
 ⚠️ **This requires disabling SIP, so run this at your own risk. Be sure to re-enable SIP at the end.**
 
-1. Disable [System Integrity Protection](https://support.apple.com/en-us/HT204899) in [Recovery Mode](https://support.apple.com/en-us/HT201314).
+1. Disable [System Integrity Protection](https://support.apple.com/en-us/HT204899) while in [Recovery Mode](https://support.apple.com/en-us/HT201314). Reboot back into macOS when done.
 
     ```
     csrutil disable
@@ -31,7 +31,7 @@ A script to fix EDID problems on external monitors in Mac OS.
     sudo ruby patch-edid.rb
     ```
 
-1. Reboot into recovery mode and re-enable SIP.
+1. Reboot into recovery mode to re-enable SIP.
 
     ```
     csrutil enable

diff --git a/patch-edid.md → README.md b/patch-edid.md → README.md
diff --git a/patch-edid.md b/patch-edid.md
@@ -2,7 +2,7 @@
 
 A script to fix EDID problems on external monitors in Mac OS.
 
-🚨 **Note: As this requires disabling System Integrity Protection, run this at your own risk, and be sure to re-enable SIP at the end.** 🚨
+⚠️ **This requires disabling SIP, so run this at your own risk. Be sure to re-enable SIP at the end.**
 
 1. Disable [System Integrity Protection](https://support.apple.com/en-us/HT204899) in [Recovery Mode](https://support.apple.com/en-us/HT201314).
 

diff --git a/patch-edid.md b/patch-edid.md
@@ -2,22 +2,39 @@
 
 A script to fix EDID problems on external monitors in Mac OS.
 
+🚨 **Note: As this requires disabling System Integrity Protection, run this at your own risk, and be sure to re-enable SIP at the end.** 🚨
 
-1. Connect the problem monitor.
+1. Disable [System Integrity Protection](https://support.apple.com/en-us/HT204899) in [Recovery Mode](https://support.apple.com/en-us/HT201314).
 
-1. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
+    ```
+    csrutil disable
+    ```
 
-  ```
-  cd /System/Library/Displays/Overrides
-  sudo curl -O https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
-  ```
+1. For macOS Catalina and newer (which uses a [read-only system volume](https://support.apple.com/en-us/HT210650)), mount the system drive read/write (yes, this is in addition to disabling SIP)
+
+    ```
+    sudo mount -uw /
+    ```
+
+1. Connect *only* the problem monitor
+
+1. Download this script in the directory containing all the display override plist files (note: even with the steps above, this command requires sudo to run):
+
+    ```
+    cd /System/Library/Displays/Contents/Resources/Overrides
+    sudo curl -O https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
+    ```
 
 1. Run the script we just downloaded (as root again). This creates a new display override plist.
 
-  ```
-  sudo ruby patch-edid.rb
-  ```
+    ```
+    sudo ruby patch-edid.rb
+    ```
+
+1. Reboot into recovery mode and re-enable SIP.
 
-1. Disconnect and reconnect the monitor.
+    ```
+    csrutil enable
+    ```
 
 Source: http://embdev.net/topic/284710
diff --git a/patch-edid.md b/patch-edid.md
@@ -2,8 +2,6 @@
 
 A script to fix EDID problems on external monitors in Mac OS.
 
-Source:  
-http://embdev.net/topic/284710
 
 1. Connect the problem monitor.
 
@@ -20,4 +18,6 @@ http://embdev.net/topic/284710
   sudo ruby patch-edid.rb
   ```
 
-1. Disconnect and reconnect the monitor.
+1. Disconnect and reconnect the monitor.
+
+Source: http://embdev.net/topic/284710
diff --git a/patch-edid.md b/patch-edid.md
@@ -1,4 +1,4 @@
-## patch-edid
+## patch-edid.rb
 
 A script to fix EDID problems on external monitors in Mac OS.
 

diff --git a/patch-edid.md b/patch-edid.md
@@ -5,7 +5,7 @@ A script to fix EDID problems on external monitors in Mac OS.
 Source:  
 http://embdev.net/topic/284710
 
-1. Connect the problem monitor
+1. Connect the problem monitor.
 
 1. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
 
@@ -20,4 +20,4 @@ http://embdev.net/topic/284710
   sudo ruby patch-edid.rb
   ```
 
-1. Disconnect and reconnect the monitor
+1. Disconnect and reconnect the monitor.
diff --git a/patch-edid.md b/patch-edid.md
@@ -1,3 +1,10 @@
+## patch-edid
+
+A script to fix EDID problems on external monitors in Mac OS.
+
+Source:  
+http://embdev.net/topic/284710
+
 1. Connect the problem monitor
 
 1. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).

diff --git a/patch-edid.md b/patch-edid.md
@@ -1,11 +1,16 @@
 1. Connect the problem monitor
 
-2. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
+1. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
 
   ```
   cd /System/Library/Displays/Overrides
-  sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
+  sudo curl -O https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
+  ```
+
+1. Run the script we just downloaded (as root again). This creates a new display override plist.
+
+  ```
   sudo ruby patch-edid.rb
   ```
 
-3. Disconnect and reconnect the monitor
+1. Disconnect and reconnect the monitor
diff --git a/patch-edid.md b/patch-edid.md
@@ -2,8 +2,10 @@
 
 2. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
 
-    cd /System/Library/Displays/Overrides
-    sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
-    sudo ruby patch-edid.rb
+  ```
+  cd /System/Library/Displays/Overrides
+  sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
+  sudo ruby patch-edid.rb
+  ```
 
 3. Disconnect and reconnect the monitor
diff --git a/README.md → patch-edid.md b/README.md → patch-edid.md
@@ -2,10 +2,8 @@
 
 2. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
 
-```
-cd /System/Library/Displays/Overrides
-sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
-sudo ruby patch-edid.rb
-```
+    cd /System/Library/Displays/Overrides
+    sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
+    sudo ruby patch-edid.rb
 
 3. Disconnect and reconnect the monitor
diff --git a/README.md b/README.md
@@ -1,11 +1,11 @@
 1. Connect the problem monitor
 
-1. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
+2. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
 
 ```
 cd /System/Library/Displays/Overrides
 sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
 sudo ruby patch-edid.rb
 ```
 
-1. Disconnect and reconnect the monitor
+3. Disconnect and reconnect the monitor
diff --git a/README.md b/README.md
@@ -1,11 +1,11 @@
-1) Connect the problem monitor
+1. Connect the problem monitor
 
-1) Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
+1. Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
 
 ```
 cd /System/Library/Displays/Overrides
 sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
 sudo ruby patch-edid.rb
 ```
 
-1) Disconnect and reconnect the monitor
+1. Disconnect and reconnect the monitor
diff --git a/README.md b/README.md
@@ -0,0 +1,11 @@
+1) Connect the problem monitor
+
+1) Download this script into your `/System/Library/Displays/Overrides` (note: this file is only writeable by root, so some commands require `sudo`).
+
+```
+cd /System/Library/Displays/Overrides
+sudo wget https://gist.github.com/ejdyksen/8302862/raw/patch-edid.rb
+sudo ruby patch-edid.rb
+```
+
+1) Disconnect and reconnect the monitor
diff --git a/patch-edid.rb b/patch-edid.rb
@@ -0,0 +1,49 @@
+#!/usr/bin/ruby
+# Create display override file to force Mac OS X to use RGB mode for Display
+# see http://embdev.net/topic/284710
+# 
+# Update 2013-06-24: added -w0 option to prevent truncated lines
+
+require 'base64'
+
+data=`ioreg -l -w0 -d0 -r -c AppleDisplay`
+
+edid_hex=data.match(/IODisplayEDID.*?<([a-z0-9]+)>/i)[1]
+vendorid=data.match(/DisplayVendorID.*?([0-9]+)/i)[1].to_i
+productid=data.match(/DisplayProductID.*?([0-9]+)/i)[1].to_i
+
+puts "found display: vendorid #{vendorid}, productid #{productid}, EDID:\n#{edid_hex}"
+
+bytes=edid_hex.scan(/../).map{|x|Integer("0x#{x}")}.flatten
+
+puts "Setting color support to RGB 4:4:4 only"
+bytes[24] &= ~(0b11000)
+
+puts "Number of extension blocks: #{bytes[126]}"
+puts "removing extension block"
+bytes = bytes[0..127]
+bytes[126] = 0
+
+bytes[127] = (0x100-(bytes[0..126].reduce(:+) % 256)) % 256
+puts 
+puts "Recalculated checksum: 0x%x" % bytes[127]
+puts "new EDID:\n#{bytes.map{|b|"%02X"%b}.join}"
+
+Dir.mkdir("DisplayVendorID-%x" % vendorid) rescue nil
+f = File.open("DisplayVendorID-%x/DisplayProductID-%x" % [vendorid, productid], 'w')
+f.write '<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">'
+f.write "
+<dict>
+  <key>DisplayProductName</key>
+  <string>Display with forced RGB mode (EDID override)</string>
+  <key>IODisplayEDID</key>
+  <data>#{Base64.encode64(bytes.pack('C*'))}</data>
+  <key>DisplayVendorID</key>
+  <integer>#{vendorid}</integer>
+  <key>DisplayProductID</key>
+  <integer>#{productid}</integer>
+</dict>
+</plist>"
+f.close