I have beta5 developer loaded and can't break into shell either. :( The first message out:

If there is anyone present who wants to upgrade the flash, let them speak now,
or forever hold their peace...it seems not. Let fly the Penguins of Linux!

is unresponsive to ctrl-c, break, ctrl-z, ctrl-x, etc...

A ctrl-A breaks into the
"pump" service. What is pump?

-chaya

SN 59, Green Display