Problems flashing latest firmware

I have a “6-Zone Konnected Alarm Panel with Siren Output” and two “6-Zone Konnected Alarm Panel Add-ons” which I bought in early 2021. I had the system up and running using Home Assistant, but it has proved too much for my technical/coding skills to maintain it. I am now trying to reset the system to use Smart Things. The first obstacle is that I need to flash the boards.

I downloaded the driver and successfully flashed one of the Add-on boards. Flashing the second Add-on repeatedly fails to initialise. I have tried resetting and I have tried pressing Boot while clicking on Install.

Additionally, the “6-Zone Konnected Alarm Panel with Siren Output” doesn’t have any lights showing. I fear it may be broken.

Can anyone help? Any ideas how to force the flashing of the Add-on board?