For zigbee this is in the zigbee binding docs. The binding maintainer @chris added it to the docs after I found it and successfully flashed my dongle. I used the docker method. If I had to do it again, I’d just use the binding method.
Flashing z-wave firmware is hard to do, very fiddly, and you run a risk of bricking the dongle. I know this because I flashed my dongle, luckily without bricking my dongle. The binding maintainer @chris advised me afterwords that it was not really useful and dangerous.
My post about this can be found at HUSBZB-1 (Combo Zigbee and ZWave stick) Should I bother flashing its firmware to latest?
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