As I was having power issues in my LibreElec uSD, I disabled my Pi3's wifi and bluetooth with the "dtoverlay=pi3-disable-bt,pi3-disable-wifi" line in config.txt. That didn't fix anything, so I commented out that line. The power issues were solved with a new USB cable.
Now, in my Raspbian uSD I find that both WiFi and BT are down. I remember that WiFi was finding only a few SSIDs (mine not included!) 10 days ago when I got my Pi3. Now I don't even have a wlan0.
As the Raspbian image that worked on day 1 was still in my computer's HDD, I have installed it into a third uSD card and same problem there: no BT, no Wifi.
Do I need any config.txt parameter to re-enable my wifi and bluetooth after that "dtoverlay=pi3-disable-bt,pi3-disable-wifi" or they just died?