So Beta 4 made my iMac un-bootable last week, I'm stuck on my nearly 10 years old MBP. What I'd like to do is download Beta 5 on my MBP, make a bootable drive, and reinstall it on my iMac b/c Beta 4 cannot be reinstalled. The Mac App Store tells me my MBP is not compatible and won't even let me download the installer! Is there anything I can do!? Thanks !