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@mauricerkelly
Forked from adaugherity/patch-edid.rb
Last active June 3, 2019 17:17
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This Gist contains the script and generated output file for an Acer B276HUL.

The pre-generated file below is known to work with:

  • OS X Mavericks
  • OS X Yosemite
  • OS X El Capitan

For El Capitan:

  1. Restart your Mac while holding Command-R: this puts your Mac into Recovery Mode.

  2. When in Recovery Mode, select Utilities > Terminal from the menu bar.

  3. In the Terminal type csrutil disable: this disables System Integrity Protection

  4. Restart your Mac and log in.

  5. Issue the following instructions:

    sudo mkdir /System/Library/Displays/Contents/Resources/Overrides/DisplayVendorID-472
    sudo cp DisplayProductID-361 /System/Library/Displays/Contents/Resources/Overrides/DisplayVendorID-472
  6. Restart your Mac while holding Command-R for Recovery Mode

  7. When in Recovery Mode, select Utilities > Terminal from the menu bar.

  8. In the Terminal type csrutil enable: this reenables System Integrity Protection

  9. Restart your Mac

For Yosemite and Mavericks:

  1. Issue the following instructions:

    sudo mkdir /System/Library/Displays/Overrides/DisplayVendorID-472
    sudo cp DisplayProductID-361 /System/Library/Displays/Overrides/DisplayVendorID-472
<?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">
<dict>
<key>DisplayProductName</key>
<string>Acer B276HUL - forced RGB mode (EDID override)</string>
<key>IODisplayEDID</key>
<data>AP///////wAEcmEDs0xgMhoXAQS1PCJ4Ikt1p1ZLoyUKUFS9SwDRANHAgYCV
D5UAswCBwKlAVl4AoKCgKVAwIDUAVVAhAAAeAAAA/QAXTA9jFgEKICAgICAg
AAAA/wBMWjJFRTAwMTQyMDAKAAAA/ABBY2VyIEIyNzZIVUwKAGM=
</data>
<key>DisplayVendorID</key>
<integer>1138</integer>
<key>DisplayProductID</key>
<integer>865</integer>
</dict>
</plist>
#!/usr/bin/ruby
# Create display override file to force Mac OS X to use RGB mode for Display
# see http://embdev.net/topic/284710
require 'base64'
data=`ioreg -l -d0 -w 0 -r -c AppleDisplay`
edids=data.scan(/IODisplayEDID.*?<([a-z0-9]+)>/i).flatten
vendorids=data.scan(/DisplayVendorID.*?([0-9]+)/i).flatten
productids=data.scan(/DisplayProductID.*?([0-9]+)/i).flatten
displays = []
edids.each_with_index do |edid, i|
disp = { "edid_hex"=>edid, "vendorid"=>vendorids[i].to_i, "productid"=>productids[i].to_i }
displays.push(disp)
end
# Process all displays
if displays.length > 1
puts "Found %d displays! You should only install the override file for the one which" % displays.length
puts "is giving you problems.","\n"
end
displays.each do |disp|
# Retrieve monitor model from EDID data
monitor_name=[disp["edid_hex"].match(/000000fc00(.*?)0a/){|m|m[1]}.to_s].pack("H*")
if monitor_name.empty?
monitor_name = "Display"
end
puts "found display '#{monitor_name}': vendorid #{disp["vendorid"]}, productid #{disp["productid"]}, EDID:\n#{disp["edid_hex"]}"
bytes=disp["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" % disp["vendorid"]) rescue nil
f = File.open("DisplayVendorID-%x/DisplayProductID-%x" % [disp["vendorid"], disp["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>#{monitor_name} - forced RGB mode (EDID override)</string>
<key>IODisplayEDID</key>
<data>#{Base64.encode64(bytes.pack('C*'))}</data>
<key>DisplayVendorID</key>
<integer>#{disp["vendorid"]}</integer>
<key>DisplayProductID</key>
<integer>#{disp["productid"]}</integer>
</dict>
</plist>"
f.close
puts "\n"
end # displays.each
@nodupe
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nodupe commented Sep 7, 2017

I've just like to thank you. My ASUS monitor suddenly became usable in Mac OS X!

@dberzano
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Thank you. You saved my day. For the record, I have an Acer B276HUL (like yours) and El Capitan instructions work with High Sierra too.

@jpage4500
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Much appreciated! Every time I upgrade my Mac I realize that I need to run this again.

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