Prevent Pi 3 from disabling wlan0

Question

I have a Raspberry PI 3 (B). I'm accessing it remotely via wlan0 - built in WiFi chip.

Now, for sake of pen testing i got myself a separate USB WiFi card. The problem is that, after i finish experimenting with wlan1, my PI disables both wlan0 and wlan1 so i can't access my PI anymore unless i connect it to a monitor and fix things while directly connected.

How to disable turning off certain device like wlan0?

Answer 1

wlan0 might go into Sleep Mode, because it hadn't been used. Check this with iw wlan0 get power_save

If the result is Power save: on, you can disable it with iw wlan0 set power_save off.

More information about iw can be found in the man page.