Pinephone wifi randomly stops working

I have a problem with wifi which, randomly, stops working. Once it has stopped working, the only solution I've found is to reflash the SD card. Then, it works again until it stops again. When the wifi is not functionnal :

ifconfig shows only local loopback interface.

sudo ip link set wlan0 up says :

RTNETLINK answers : Operation not possible due to RF-kill

rfkill list says :

0: phy0: Wireless LAN

Soft blocked: yes

Hard blocked: no

Then :

sudo rfkill unblock 0 is ok.

sudo ip link set wlan0 up is ok.

sudo iw wlan0 scan shows my wifi network.

I don't know what to do next. Rebooting the device makes wlan0 blocked again.