In message [ref] you wrote:

thank you so much for your helpful reply. No, I don't have a serial 
port that works "out of the box", and your hint of setting up the MMU 
translations and poking characters at hard coded addresses, is a big help.

Also remember that you can often get a lot of useful information from
a post-mortem dump of the lug buffer - see
http://www.denx.de/wiki/view/DULG/LinuxPostMortemAnalysis

Finally a wild guess - did you include a "-b 0" option when compiling
your device tree?

Best regards,

Wolfgang Denk

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DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
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