Can not get board to boot up reliably

[pfeerick]

just a note that if you do not use ethernet the boot has to wait for a timeout and it's a fairly long time so you might think it is not booting.

Fairly long being 5 minutes  (or 300 seconds) IIRC :-P 

This is starting to look like the WiFi driver being a pain again, unless it is still the ethernet waiting for the link to be established.

When you say no WiFi connected... do you have the WiFi module, and is it installed?

Try editing /etc/network/interfaces so that it says

Code:

auto lo
iface lo inet loopback

allow-hotplug eth0
iface eth0 inet static

(i.e. remove the 'auto eth0' line as I'm pretty sure it isn't needed when you do allow-hotplug.) 

Other than that, hard to say .... you've done most of the normal troubleshooting and tests.