Boot Error

[starsu at media.mit.edu]

Dear all,

I updated build 613 into 650 on B4 Machine. For some time, it worked  
well. However, after several reboots, when XO restarts, the following  
boot error occurs.

Boot device: /usb/wlan Arguments:
Scan for: OLPCOFW
Cannot find: OLPCOFW
<buffer at ff838c2d>:0:
Can't open boot device

Can you kindly let me know how to deal with this boot problem?

Thanks,

Sung-Hyuck