[coreboot] T520 vs. T530

[Nico Huber]

On 10/23/18 7:59 PM, Michał Kopeć wrote:
>> 1. I need CPU power. I read that it is possible to put a i7-3940XM in a
>> T530. Because of coreboot it should also possible to put it in a T520?
> Yes, with Coreboot you can put an Ivy Bridge CPU into a xx20 series
> ThinkPads.

It works sometimes. AFAIK, nobody has figured out yet which combinations
work and which don't. Might depend on the processor stepping, the ME
firmware version, DRAM clock etc.

Though, with some patience you'd likely get it to work.

>> 3. With which model it is easier to install coreboot on it?
> No practical difference, the building and flashing procedure is the
> same.

Actually, there are many differences, IIRC. The T520 has a single flash
chip. The T530 has two. And, AFAIK, the T530 lacks pull-ups on the flash
chips' /CS signals. Which means you have to connect both chips' /CS pins
appropriately to access any of them.

>> 4. What are the general pros and cons of a T520/T530, especially with
>> coreboot?
> T530 will not accept non-Lenovo batteries unlesh you flash a patched
> EC firmware, and that can only be done while you're still running
> stock UEFI. T530 has USB 3.0, T520 has a keyboard that some consider
> superior. Otherwise the machines are extremely similar.

The initialization of the T530's USB 3.0 controller is incomplete. You
could use a reference-code blob though (or use the blob's results to
fill the gaps in the initialization routine).

Nico