My Raspberry Pi 4 kept losing its wlan0
interface. I could usually reconnect via Ethernet but, from time to time, I noticed that the eth0
interface would also go walkabout.
I tried a lot of things but the one described here seems to have cured the problem. I have no idea why it works. It just does.
The script shown in the next step should be created on your Raspberry Pi. Please do not make the mistake of selecting the text, copying it into a text editor on your Windows machine, saving the file, and then moving the file to your Raspberry Pi. Unless you take precautions, Windows will add its 0x0d 0x0a
(CR+LF) line endings and those will stop the script from working properly on your Raspberry Pi.