RAK811 reset default setting

LPWAN Modules / EVBs RAK811
1

Issue:
Dear all,
I am running with EU433 but when run a long time i saw rak811 auto change CN470, so it is not working anymore. I have 2 question:

  1. How to reset default setting EU433 as first time?
  2. When we frequent (about 5-10 mins) change setting such as tx power, datarate… then it make rak8111 short life or mess up setting?

thanks and regards,
Setup:

Server:

Details: