IP truncated-ip - 4 bytes missing!

Hi,

I'm using at76c503 driver for Linksys WUSB11 on Sharp Zaurus
(OpenZaurus 3.5.4.1, kernel 2.6.16) and have a very very odd problem.
Only ping -s 14 192.168.1.1 does work! Nothing more than 14 bytes come
IN! But anything above go out (56 bytes...)!
If I do a normal ping (56 bytes), all 56 bytes go out, I see that
because I've listening tcpdump on target machine. But reply doesn't
get back completely. Looks like a leck somewhere.

Here's what tcpdump says about incoming traffic (ECHO REPLY), if I
send out more than 14 bytes at once (ping 192.168.1.1):

"IP truncated-ip - 4 bytes missing!"

I'm using at76c503 CVS, cross compiled with OpenEmbedded.
USB device is wlan0.
There is an externel powered USB Hub, where WLAN Adapter is connected to.
To load at76c503 driver I have to do a modprobe -f at76c503 at76c503_rfmd.
Force "-f" because kernel says "version magic '2.6.16 preempt ARMv5
gcc-4.1' should be '2.6.16 preempt ARMv5 gcc-3.4'. But that shouldn't
be the problem?

Today morning after powering on machines, USB-Hub, a normal ping with
56 bytes did work directly! I was surprised, but I couldn't reproduce
it after that.

Something odd...

Any suggestions?