I had the same problem installing windows 7 and found this fix. While it may not work on Ubuntu, It may give you some direction. I'm resigned to just use my external monitor for Ubuntu.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/597070 Title: Imac Radeon HD 4850 switch "Mini Display Port" output during install resulting black screen To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/597070/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
