[HELP] Changed build prop not booting anymore topic

I restored a build prob where I added 3 ril lines. now the phone won't boot. I can do a reboot of some kind with power and volume up but then the screen goes blank.
At the time I was trying cm12 latest and reverting to cm 12 of 1-28. The build prop was also from that 1-28. I thought it could do no harm but it did.