Of course, I have also gained root, and found that the command does not result in success for me either.
Using the uname -a command results in a string of information ending with; arm71 unknown... will post the full string later when I get back

*Linux Nokia-N900-42-11 2.6.28-omap1 #10 PREEMPT Sat Apr 3 09 :01:04 EDT 2010 arm71 unknown*