I used the HP tool version 2.1.8 - there should be 2.2.3 and 2.2.4 somewhere but I kept coming up against WoT warnings when I tried to download them.

Still can't boot, waited 8 minutes with a blinking cursor all alone in the top-left corner.

The resurrected MSI Wind forums (they had closed down, don't know Ins & Outs) don't have obvious help for this "issue", but I am going to have another root around there.