T420 now works with IVYBRIDGE CPU here are the Coreboot builds

I have uploaded my build for T420 to use IVYBRIDGE CPU, if anyone want to try. https://www.dropbox.com/sh/mq1e2a54vv030nz/AAAgPSRYlPhuXiZiRE9qJbwQa

There are 10 roms with different MAC addresses (gbe.bin) for sandybridge and another 10 for ivybridge (I tried to link vgabios, but does not work. So I build two sets). The reason for having 10 different MAC addresses is if you have several laptops plugged into the same router, you need different MAC addresses.

Some features:

1. Support Sandybridge and Ivybridge CPUs (I tested i7-3xxx QM) (by changing the vgabios name code) 2. No whitelist you can use any wireless card 3. Unlock RAM speed to 1866 (due to chipset limit 1866 is the highest) 4. Works with Windows 7,8,10, linux (Seabios） 5. Works for both t420 (with/without Nvdia graphics card) 6. Updated vgabios to newest 2170 version 7. Removed useless intel management engine (AMT)(Replaced 5MB ME region with 1.5MB ME) 8. Have 10 MAC addresses you can choose

For how to flash https://www.coreboot.org/Board:lenovo/t420

Some pictures on how to wire out the pins. http://imgur.com/a/OFUN4