Guys the general thinking is VZW is off the air on Sunday nights for their maintenance update window.
Please try reflashing after 0800 Monday morning (that's in 3 hours after this post).
As the PP pointed out, other than flashing an SBF you cannot undo the baseband upgrade. IN ANY CASE even if you flashed the previous baseband you'd still need an upgrade.
Please wait roughly 3 hours from this post... try again, and PLEASE let us know here if it works, and if you had to do anything special. Odds are it will "just work."
0208 MST (UTC - 0700)