lifebook u729 - replace sierra with extra ssd

Hi all,

i recently bought a nearly mint 729u from one of the enterprise lease/resale companies out there (it was really pristine) and i immediately replaced its 512gb ssd with a 1tb nvme. All good so far. She boots up very quick and i'm really happy about the low weight of it (as i'm taking it on travels were that counts).

But lately i was curious to try to find out if the sierra 4g card (m.2) could be replaced with a secondary ssd (sata m.2) that would perhaps even allow the machine to boot from this secondary device, without hitting some whitelisting issues (?) and so my question is really:

- Does Fujitsu enforce whitelisting on this slot?
- If no, can the machine boot from this slot (via boot select)?

I'm thinking about installing linux on the (potential) ssd and choosing OS by means of an F-button. But is it possible?

 

Any progress? I have a U745, and am thinking about making use of that m.2 slot.
I know you can do that with a Lenovo, but not sure of Fujitsu, especially one made in late 2015.
If an SSD doesn't work, I'm considering buying a connector in which an SD or TF card can be inserted. Many people say that slot doesn't work vary fast, so you can't make full use of the SSD's speed. Thus is an SD/TF more reasonable choice, since it's not so quick anyway?