For purposes of Fido/U2F, almost every service that lets you use U2F will also let you set up TOTP, and with TOTP you can save/print the QR codes. And TOTP is good enough to let you enrol a new U2F key.
So you don't need the expense of buying multiple yubikeys if most of them will end up in safety deposit boxes. Just put a printout of a TOTP QR code in the safety deposit box.
(This doesn't apply if you want to use the non-U2F features of the yubikey, like PGP, but who needs that?)
So you don't need the expense of buying multiple yubikeys if most of them will end up in safety deposit boxes. Just put a printout of a TOTP QR code in the safety deposit box.
(This doesn't apply if you want to use the non-U2F features of the yubikey, like PGP, but who needs that?)