I've uploaded a fix for the -psb X issue to PPA. [1]
Yesterday, Amit and I found that a psbDRILock() routine was being called
twice; this routine requests a lock in the kernel, which works the first
time, but not the second.
So this morning, I disabled the second lock/unlock in -psb[2], and sure
enough, X came up and seems to be working as expected now[3].