7d22ef28e64de06b6238d0ef9b664c0bee6efa46 Build or download BA from AB. After it boots all you get is a terminal, HOB should have started. Seems to me there are two issues in /usr/bin/x-session-manager (one missing space for the if test and the su which doesn't run...)
I am working on this, there was a problem with the http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=982eefe22dba0f007010465e31d5d6adcc59e4d0 patch, it introduced these 2 issues, first by not leaving a space before the "]" and then using su instead of sudo.
In this case the patch were merged wrong. I sent two revisions of it. Those errors were in the first and fixed in the second.
BTW: I only saw one version! http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/?id=3312a2fd9097636fccd7c439369926a806956221
Verified in 1.4M5.rc1.