Since it uses a 2 of 3 multisig wallet, you need any two of the following to have (or regain) control of your funds:

• Mobile key – A key stored in the Bitkey app on your phone.
• Hardware key – A key stored in the hardware wallet device.
• Server key – A key stored in a server operated by Block Inc.

If you lose the second and the third is unavailable, you will lose your ability to spend money.

The only obvious way around this is to have a backup of the hardware key, know how to set up a different wallet application as a 2 of 3 multisig wallet and have any other relevant information such as derivation paths.

The only way I think you can satisfactorily prove you can recover from that scenario is to actually practise recovery and use non-Bitkey software to make a test transaction spending a small amount.