#!/usr/bin/ruby

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

Usage: pkgutil [OPTIONS] [COMMANDS] ...

Options:
  --help                 Show this usage guide
  --verbose, -v          Show contextual information and format for easy reading
  --force, -f            Perform all operations without asking for confirmation
  --volume PATH          Perform all operations on the specified volume
  --edit-pkg PKGID       Adjust properties of package PKGID using --learn PATH
  --only-files           List only files (not directories) in --files listing
  --only-dirs            List only directories (not files) in --files listing
  --regexp               Try all PKGID arguments as regular expressions

Receipt Database Commands:
  --pkgs, --packages     List all currently installed package IDs on --volume
  --pkgs-plist           List all package IDs on --volume in plist format
  --pkgs=REGEXP          List package IDs on --volume that match REGEXP
  --groups               List all GROUPIDs on --volume
  --groups-plist         List all GROUPIDs on --volume in plist format
  --group-pkgs GROUPID   List all PKGIDs in GROUPID
  --files PKGID          List files installed by the specified package
  --lsbom PKGID          List files in the same format as 'lsbom -s'
  --pkg-groups PKGID     List all GROUPIDs that PKGID is a member of
  --export-plist PKGID   Print all info about PKGID in plist format
  --verify PKGID         Verify file permissions of the specified package
  --repair PKGID         Repair file permissions of the specified package
  --pkg-info PKGID       Show metadata about PKGID
  --pkg-info-plist PKGID Show metadata about PKGID in plist format
  --file-info PATH       Show metadata known about PATH
  --file-info-plist PATH Show metadata known about PATH in plist format
  --forget PKGID         Discard receipt data for the specified package
  --learn PATH           Update --edit-pkg PKGID with actual metadata from PATH

File Commands:
  --expand PKG DIR       Expand the flat package PKG to DIR
  --flatten DIR PKG      Flatten the files at DIR as PKG
  --bom PATH             Extract any Bom files from the pkg at PATH into /tmp
  --payload-files PATH   List the paths archived within the (m)pkg at PATH

localip 192.168.0.1
remoteip 192.168.0.234-238,192.168.0.245