V3 with PyCom Lopy4 LoRa nvsram restore issue

[descartes (Nick McCloud)]

@teus

We also noticed that the first LoRa datagram after a join (f_cnt = 0 probably) is not present as “f_cnt”:0 in the MQTT json data record.

That’s a standard gotcha that comes with Google Protocol buffers, see:

First f_cnt is empty/null - world wide technical debt in progress

Please be aware that at present the first f_cnt is empty/null aka not 0 so anyone writing any form of integration will need to handle this as any reasonable database should be validating the f_cnt as a number. See First f_cnt is empty/null · Issue #3874 · TheThingsNetwork/lorawan-stack · GitHub

The question is, if you hotwire the f_cnt by one, does it then store the new value.

Or put another way, does it ever increment.

I’d go back to PyCom and invite them to fix this immediately - if they are storing the f_cnt wrong it shouldn’t be that hard to store the new one AND it rather makes the whole functionality totally useless without the f_cnt being stored.