I just upgrade my Mini 9 from 10.5.6 to 10.5.8. (I am running a 16GB Runcore with 2GB RAM). 10.5.6 was very stable, but I have had problems that other have mentioned here with 10.5.8, especially losing WiFi after sleep. Specifically, after I wake from sleep, the WiFi/Airport icon in the menubar disappears and the OS hangs (spinner). I have used both EFI 1.1 and EFI 1.2a5 in every permutation, including deleting/recreating custom dsdt file and reinstalling extensions. Is there a different solution I missed? I am not a n00b installer.
I ran across another problem. If I use EFI 1.2a5 instead of EFI 1.1, the OS hangs at boot time (gray screen). This appears to be related to installing Chameleon 2.0 Bootloader. If I install PCEFIV9 Bootloader from EFI 1.1, reinstall extensions and create custom dsdt file in EFI 1.1, the OS boots appropriately (although the WiFi hang after sleep is still present). If I install Chameleon 2.0 Bootloader, reinstall extensions and create custom dsdt file in EFI 1.2a5, the OS hangs at boot (gray screen). Weird! Any explanations out there?