I just finished mine up 5 minutes ago and it did the same thing. I found out what it was: POWER  I was running it off a 9v battery with about 8.1v in it, it would go positively apesh*t on the MIDI out port just like that for about a minute then it would just sit there dead.  I stuck a brand new 9v on it and it booted right up.  Now i've got to get some apps on there to test it out.