Found the solution to macbook 4,1 mountain lion install. Someone already worked out the issues!
parrotgeek.com
One note is where is says "cd to this directory", you have to cd into the unzipped directory where .oipatch.sh is. If you move this script away from this folder or execute the script from another directory, it will not produce a properly booting installer (will show up as bootable, but gets a crossed out sign when booting it)
Used this solution, made a USB installer. Installed ML (10.8.5). My appstore auto updates failed (10.8.5 supplemental and few other items) but was able to manually install these one by one (run appstore to get the list)
- first browser downloaded the security update 2015-006 for mountain lion. Installed and rebooted.
- tried to install 10.8.5 supplement (browser downloaded) and installer say ML partition doesn't qualify (appstore never suggested it again)
- manually installed airport utility and itunes pkg downloaded from browser
- use appstore to do the remainder (remote desktop, appstore 1.0 etc)
After all updates done, ran mllegacygfx.pkg and bingo, kernel is switched to 32b and X3100 drivers loads properly.