I was having the same problem that it would not update via OTA. I opted to use the wired method with the Verizon update assistant. Also, my update was not 600 MB, it was like 2.1 GB.
gTablet ( TNT Lite 4.4.0 )
HTC Droid Incredible ( OMFGB 1.1.X )
HTC Droid Incredible ( SkyRaider 3.5 )
HTC Droid Incredible ( Cyanogen 6.1 )
HTC Droid Incredible ( Stock Sense 2.2 )