So after much fiddling yesterday my AR2413 based DWL-G510 rev. B PCI NIC would not work with ath5k - when linux was booting and 'loading hardware drivers' "phy0 POST failed !!!".

But later that night I was doing more fiddling, following a WPA crack tutorial, and ran
airmon-ng stop ath0

Expecting it to not work (hoping an error would give more clues as to how to fix the problem - getting desperate), but it did! I spent all night trying to capture the 4 packet handshake blah blah blah.

But since I haven't gotten it working, with BT4-beta or pre-final.

Is there anything at all that could be working some times but others not?

I'm stumped