OT: How to debug MIC failure from wireless chip?

[Chris Phoenix]

I'm getting through the 4-way handshake, which means I'm handling the
keys correctly (thanks, Jouni!). So I send the key material
(sm->ptk.tk1) to the chip, according to its documentation and
following the driver code I got from them, and I get a return code of
0 (success).

Then the "data" packet arrives (the Group 1/2, I guess). And I get a
MIC failure event from the network chip at that time. Just one event,
though the AP sends 4 data packets and then a deauth, one second
apart.

The CPU is an ARM; the network chip is a Wi2Wi W2SW0001. The AP is a
Belkin running WPA; my cell phone connects to it, and I see the AP's
data packet replied to, and that's the final transaction for them.

Does anyone have experience with this wireless chip? Anyone have any
thoughts on how to debug, other than reading and re-reading the code
until my remaining hair falls out?

Thanks,
Chris

-- 
Chris Phoenix
cphoenix at gmail.com
650-776-5195