Updated to latest master and have a problem

[elekktretterr at exemail.com.au]

Hi all,

Ive updated my machine to the latest master to try devfs. Ive run
buildworld,installworld,buildkernel,installkernel and make upgrade and
then restarted and I get the mountroot prompt saying this:

hammer_mount: volume /dev/ad4s1b has an invalid header
Root mount failed: 79

mountroot>

What did i do wrong and what can I do to fix this? Was I supposed to rm
/dev before running make upgrade or something like that?

Petr