Failure when frame counter reaches 65535 (mDot v2.0 firmware issue?)

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1

I’m seeing evidence that this bug has cropped up again. Basically, the frame count in lora-app-server does not go higher than 65535 and loraserver reports “invalid fcnt or mic” . Can anyone confirm?

https://github.com/brocaar/lora-app-server/issues/6

2

I’ll see if I can reproduce this issue tomorrow. Please report bugs at the GitHub repo in the future :slight_smile: The forum is better for discussions, the GitHub issues better for bugs / tasks. I did see you posted a comment on GitHub, but then you removed it again? What is the type of your node (vendor, type, node firmware)?

3

Great, i’m using Multitech mDots with the 2.0 firmware.

Thank You

4

Looks like this has something to do with the mDot firmware. I’ve updated to the latest version (3.0) and no longer see the issue.

Thanks!

1 Like
5

Great, I was about to start debugging this :slight_smile: Note that the device only transmits the 16 LSB of the (usually) 32 bit frame-counter, but uses the 32 bits to calculate the MIC. Maybe the v2 firmware did not use the 16 MSB for the hash calculation?

(I tried to reproduce this with a RN2483 device, but I don’t see any issues when the fCnt reaches 65535)