The MiFi 7730L cannot be updated without being on the Verizon network (it presents such a message to me when I try). A Project Fi data SIM works fine in it, but I cannot update the software.

What are my options?
1) Can I borrow a friend's regular VZW smartphone SIM, or is a SIM with a hotspot plan required for the software update?
2) Can I use a MVNO prepaid SIM (on Verizon network), or does it have to be a Verizon branded SIM?

Any thoughts are appreciated.