SL with Ati 4850 - blank screen after installing kext

[Cantello]

Hey all,

I have semi-successfully installed SL following Tony's guides. However, with my Radeon 4850, the only way to get a GUI was to use the "-x" flag for safe mode.
Now I wanted to get rid of this and installed LegacyATI4800Controller.kext from netkas.org.

The only change was that now the screen goes blank immediately after the boot process and I am not able to get a GUI, not even with "-x".

Two questions: what can I do to get at least my safe mode back?

And secondly and more importantly: What exactly am I supposed to do with my graphics card. Is there an up-to-date guide for these things? I most probably got confused and incorrectly installed a kext that was not really necessary. Some people say that only a change in the boot.plist is necessary, others say that I have to install kernel extensions...

Could someone please shed some light on this for me?

 

[wlp5]

Use the tony's bootcd to boot back to your installation in safe mode and undo your changes.

As for the fix, I have the same card and eventually fixed everything besides sleep. I did it with graphicsenabler=y, netkas kexts and editing a kext to include my card's id. Can't really remember everything now. Search for my posts (same login) in the insanely mac p55 thread, play a little and come back with more questions if you can't get it.

 

[Cantello]

Use the tony's bootcd to boot back to your installation in safe mode and undo your changes.

I don't even get a desktop with Tony's boot CD... :-/ Somehow I guess that my video output is now routed through the HDMI port instead of the DVI port (I have a Club 3D card with DVI + VGA + HDMI).

Will try removing Legacy4800Controller from Windows via MacDrive but I am not sure if this will work as I cannot rebuild the kext cache while in windows.

 

[oitx4nth0ny]

try the ATI bootsCD at the bottom of the tutorial.

 

[wlp5]

Here's an idea that should work in theory but haven't tried it myself. Boot with the bootcd, and then swap to the install dvd, in safe mode of course. When you get to the welcome screen, open up terminal. Delete the kext file (note that your disk is now under /Volumes ) and then rebuild the caches.

I found these commands by googling

kextcache -v 1 -m /Volumes/[CHAMALEON DISK]/Extra/Extensions.mkext /Volumes/[CHAMALEON DISK]/Extra/Extensions/ /Volumes/[SNOWLEOPARD DISK]/System/Library/Extensions/
  
  kextcache -v 1 -m /Volumes/[SNOWLEOPARD DISK]/System/Library/Caches/com.apple.kext.caches/Startup/Extensions.mkext /Volumes/[SNOWLEOPARD DISK]/System/Library/Extensions/

In your case, both of these disks might be the same.

 

[Cantello]

Here's an idea that should work in theory but haven't tried it myself.

Thanks wlp5, this one worked!

Several tries later, I again had a blank screen after SL should switch to the GUI, but this time I had a hunch that it would work (okay, plus I read approximately 500 posts on this issue) and bought and pluuged in a HDMI->DVI adapter (a complete cable in my case). Voilà, GUI in full resolution without safe mode!

Now I only have to get sound to work...

 

[wlp5]

There is an interesting thread about 4850s at insanelymac->post-installation that you might want to check out too.

By my understanding, there are more than one ways to fix garbled screen/blank screen. Myself I will try alternative methods over the weekend as I still get a garbled screen after waking up. Though I don't use sleep, it'd be good to fix it for future updating...