edit :

/Library/Preferences/SystemConfiguration/com.apple.Boot.plist

with :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
<key>Kernel</key>
<string>mach_kernel</string>
<key>Kernel Flags</key>
<string></string>
<key>Boot Graphics</key>
<string>Yes</string>
<key>Graphics Mode</key>
<string>2400x600x16</string>
</dict>
</plist>




save the file on DESKTOP do not save the file in /Library/Preferences/SystemConfiguration/
( do that only if you know how to manage permissions )
If you don't save it on desktop . Same name . TXT editor will ask if you want to use txt exstention or plist . USE plist .

Once you save it . Drag the new file from Desktop to /Library/Preferences/SystemConfiguration/

Finder will tell you that the folder it's protect and will give you the option to autenticate your self as admin . use your admintration user and password .

BOOM ! that's it , you mac will boot start always with 2400x600 resolution .

any damage it's on your own risk

E