Linux Kernel Crash Apalis T30 with AR9285

I have followed directions to build a new u-boot and 2.6 kernel for the Apalis T30, adding in Atheros ath9k PCI/PCIe bus support. I installed an AR9285 based WiFi card in the PCIe slot on my Apalis Eval board, and reflashed the T30 with the new OS. Everything boots up fine, the card appears in lspci. I then enable WiFi in connmanctl-properties, and I add wifi.config to /var/lib/connman:

Type = wifi
Name = MySSID
Security = wpa2
Passphrase = xyzzy

The wifi card then properly connects to the network and I can ping other machines. Problem is that this works for up to a minute and then linux locks up. Sometimes it doesn’t even get through the boot process.

Can anyone provide any guidance - have I missed a step? I assume that this driver/chipset is known to work but perhaps not?

I also have no idea where to go now to debug this. Console connected via USB does not respond, nor does sysreq key (I also enabled that in the build).