I have successfully followed cerastez's guide to installing retail 10.6.8 on my GX620 SFF, and have a couple of observations and remedies, with one outstanding problem. I would welcome your thoughts and suggestions on any and all of these!
1. The GX620 SFF only has VGA video, and when I built my DSDT under 10.6.3 video was good (1440x900) until I applied the 10.6.8 combo, after which I got the dreaded secondary display only - i.e. the grey desktop background, mouse was movable and visible and I could right click to display a context-sensitive menu etc. To resolve this, I restarted with a fresh 10.6.3 install and waited until after 10.6.8 to generate and patch my DSDT.aml. Rebooted and all was good.
2. Using 32-bit legacy kernel, I have everything working just fine (video is 1440x900, internal audio is AC97Audio with IntelICH personality and AD198x codec), so I added an RTL8129SU based USB wireless controller with 10.6 drivers from Realtek here. Now, with this installed, I get wireless but it fails after a few minutes and I need to reboot. Nothing is really reported in system.log other than a network reconfigure right before the network fails. Perhaps someone else is using these same drivers and has problems in 32-bit 10.6.8 legacy kernel ?
3. I changed to 64-bit kernel by adding <key>Kernel Flags</key><string>arch=x86_64</string> to com.apple.Boot.plist. I have had great success with 64-bit kernel, with one exception. Wireless is rock solid, video is great, but any audio event causes a kernel panic (double panic). Obviously I can live without audio, but want to get it working. I have searched and found a number of AppleAC97Audio.kexts that are advertised to work/might-work in 64-bit mode, but all of them have caused the kernel panic. The troubleshooting I have done to-date is to edit the Info.plist of AppleAC97CodecAD198x.kext which had the following <string>ADS75 ADS74 ADS73 ADS72</string> in the the AD198x key. I understand these are vendor version-ids from Kykops' fix. Not knowing exactly what to put in there I played around and know that when the string is:
ADS75 ADS74 ADS73 ADS72, I get no audio
ADS78 ADS75 ADS74 ADS73 ADS72, I get a little blip of the correct audio followed by a kernel double-panic
At this point, I am so close I am sure there's a solution, I just don't know really what I'm doing in the config of the AppleAC97CodecAD198x.kext config.
After this long post, I don't understand why in 32-bit mode the Realtek driver was a problem, indeed it may have been something else. I don't really need to be in 64-bit kernel (I only have 2.5GB RAM), but it really stable except for the audio crashing the system.
I'd love to hear from any of you with some suggestions on how to troubleshoot or what to try.
Thanks to cerastez who replied to my PM, and getting me over an earlier hurdle.