nucleol073rz's App_eui keeps changing to 0

[sjung.11]

I'm using nucleo l073rz and I'm trying to connect to Chirpstack.

But it doesn't have an uplink. When I checked the JoinRequestMessage, all contents of App_eui were zero. I set it to the original App_eui using the serial port, but it returned to zero in a day.

Why is this happening repeatedly?

[Tesla DeLorean]

You're updating/erasing the firmware? Or its not using OTP to store permanent data.

Suggest viewing code.​

[sjung.11]

I don't understand what you mean.

Also, when all Appeui changes to zero, Appkey also changes to 11 22 33 44 55 66 77 88 aa bb cc dde eff gg hh.

What's the problem?