I haven’t updated mine. I’m guessing that the firmware is upgraded using their own software.
Old reply , but the fw is upgraded from z-wave.me’s software. It’s always easiest to install this first on a new PI, then disable z-wave server and install homeassistant (everything regarding the device itself gets setup for you).
Hello
I have tried forever to configure a RaZberry2 daughter board on my Raspberry Pi 3 B+ already running latest version of Home Assistant 0.87.1. I have tried configured z wave from GUI and from configuration.yaml, but no matter what I do, the Raspberry/HA will not boot. I cannot get in touch with it and it does not respond on ping.
I really hope someone can help me out 
Jens