Hi Peter,

quoted

Peter, I dunno if you are already aware of it, but the USB peripheral
mode hangs
on MX233. It's easy to replicate for example if you try to run CDC
ethernet over
the USB peripheral mode, then telnet into the board and run "dmesg" .
This will
trigger a "larger" data transfer which will make the UDC driver hang.
This
doesn't happen on MX28 so it must be some MX233-specific thing.

Marek, Have you tried below?

http://marc.info/?l=linux-usb&m=136537318510847&w=2

It may not the USB itself problem, the mx23's usb is almost
the same with mx28's.

This also happens on a different MX23-based board for me. This other board I 
tried has mDDR DRAM and the DRAM is operating correctly. The 96MHz thing people 
complained about in the Olimex forum is resolved now. 

Best regards,
Marek Vasut