Hi there! I have a iMac 27 i7 3,4ghz mid-2011 and it was shipped with Lion. I do wanted to have SL installed instead of Lion and end up with installing with restore option with a 10.6.8 DMG restore via Disk Utility, and it worked. I had SL without any problems til today, when i boot up imac i have the famous "ACPI" boot kernel panic (it seems to be a problem with the thunderbolt update that is causing this) Now i see that everyone say that i should re-install SL and then re-do all updates but ignore the Thunderbolt update. But when i insert 10.6.3 retail disk then i get 3 beeps and cant start the install. Does anyone know if my iMac can boot from 10.6.8 install disc, and if so, how can i get it as a installer disc?