Updating Razberry firmware - how to allow serialupdater tool to access device

(I have a gen 5 board, btw)

Important note:
I eventually got to the bottom of my Z-Wave RaZberry troubles, and it started with the firmware upgrades on this page, I believe.
Somewhere along the process, the frequency was changed from US/Americsas to EU.
The command line script for changing the frequencies no longer worked (although you wouldn’t know it when running it). The Z-Way interface only provided the option to switch between EU/RU/CN/IN - no US.

The solution was sent to me by the z-wave.me team today. The frequency can also be changed by web interface.
Stop openhab, start z-way, and log in through port 8083
then navigate to/run

IP:8083/JS/Run/zway.ZMEFreqChange(3)

This then finally changed the frequency correctly, as evidenced by
IP:8083/expert/#/network/controller > show controller data
and I am now finally able to add and control devices.

Ugh, this was a long process to sort out!

Ben