Originally Posted by mancha
OK. This is helping us get to the problem.
Let's try the low-hanging fruit first. The multiple disconnections could be related to a stale or multiple wpa_supplicant instances. Let's get rid of them all:
Also, in NM-applet, how have you configured your Wifi-security? WEP 40/128-bit key? I suggest you input it as hex.
If these things don't work, let's move to Plan B.
Killing wpa-supplicant didn't help but using WPA2 instead of WEP (configured 40/128-bit input as hex, I confirm that BTW) did
I'm marking this thread as solved, though TBH I didn't actually understand what was going wrong
and why it works now.
Anyway all is well that ends well.
Thanks everybody, especially mancha.