I had Mavericks installed I downloaded Yosemite from the App Store. Followed the earlier guides and prepared a usb. After a lot of reading and different boot tags I was able to install it on a partition beside Mavericks.
I had to use nv_disable=1 Graphicsenabler=yes npci=0x2000 cpus=1. Everything worked good. installed a few kexts VoodooHDA for Audio, NullCPUPowerManagement, kext for CMOS reset.
Everything is working fine but because of cpus=1 system is running on only one core. I replaced kernel, I also patched kernel but no luck, installed VoodooTSCSync kext but didn't work. with all these options I get kernel panic after the boot. I even tried cpus=2, 3, 4 but system boot normal but after a few mins kernel panic; Sometimes it is panic(cpu 3 some times it is panic(cpu 2 and so on.
I get same issues with Mavericks when not using cpus=1.
Anyone please help me and guide to right direction..
I have updated yosemite to 10.10.1. Got minor issue of CMOS reset but fixed it after searching it online..