Sorry but T450S is not supported by coreboot.
Here is a list of laptops that ARE supported:
On Mon, Aug 27, 2018 at 4:23 AM Brian Herman
I am in contact with a person with the means to reprogram a T450S.
What would I have to do to make coreboot work?
I think I would have to have two laptops or at least motherboards right?
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