I have tried numerous kexts and have not been able to get Ati 5450 working in 10.8.5 Mtn Lion it will not boot to any video screen. Any thoughts or basic steps .
Also what video cards will work . Used Izztech bios link and had no problems installing 10.8.2 with intel 4000 enabled. Just no go with anything else I had laying around. Quo Motherboard. and latest bios.(H3a 816m)