OSX Mavericks \ Yosemite on a T520 - i7 16GB 256GB SSD
So I was interested in getting OSX running my my T520. I had looked into this about a year ago with no luck, but now there is a great write up for it by the guys over at insanelymac.com on how to do this.
After doing my own research to get the required parts , software etc I now have a core i7 , 16GB (ill explain later) , and a 250GB SSD that makes OSX scream on this awesome piece of hardware.
So to get started the first thing you are going to need is a whitelist bios patch for the Bios and can be found here:
Get the 1.44 versoin and flash your bios per the readme included, once its flashed install a OSX compatible WiFi card.
Lenovo locks their laptops to intel only WiFi cards. Unfortunately there is little to no support for these on OSX so the best thing to do is replace it with a compatible card. These can be found on ebay for about $5.
In my case I purchased a used Atheros AR5B9 for $2.50 shipped, just search for AR5B9 and you will find tons of them.
Next you will need a working OSX install (I started with Lion) on a real MAC or a virtual.
Either purchase the CD or USB from Ebay or where every you can because Apple does not sell this any more. If you are using a virtual OSX , you can use virtualBox or VMware workstation. ( I prefer workstation).
If using Workstation you will need an applicatoin to 'unlock' OSX features in Workstation.
Again insanelymac.com has this post, just down load the unlocker, run it, then install OSX.
First go to the this page and download the T420_UEFI-Clover-b3048_10.9_10.10_2014-12-04.zip , it will require you to register, then start at the point where it says "INSTALLATION GUIDE"
Once you finish the install, and install Clover and the kexts you should have a fully working OSX install.
One note however if you goto download the hwmonitor and replace FakeSMC.kext , audio no longer worked for me until i re-installed the FakeSMC.kext
At this point OSX looks great. But for some of us we want to use the T520 as a production workstation. So if you do not already have a docking station, get one! This is the best way to connect an external monitor and use your t520 as a desktop. I already had one but again on ebay looks like they are about 20 bucks.
Make sure you change the file Platforms.xml.zlib.dock to Platforms.xml.zlib , just search Platforms.xml.zlib.dock in the insanelymac link
Now I still need a Windows OS to do some other work, this is where VMware Fusion comes in.
Install Fusion, install Windows, Done!