this should say something like this in the top line:
BRAVO PVT4 SHIP S-ON.
This seems to apply to -NEW- PVT4 devices only.
Apparently there are some older ones named PVT4 as well.
Check using the following:
cat /proc/mtd (from adb shell or terminal emulator)
Erasesize will say either 20000 or 40000, whereas the last one identifies your device as being PVT4 New. This has a different NAND chip, which uses a bigger pagesize and changed partition offsets.
Tools will need to be adjusted to work with this change (for example, ClockWorkmod, AlphaRev, and some custom ROMs.)
Check out AlphaRev 1.8 at http://alpharev.nl , that should install HBOOT S-OFF for these PVT4 new devices now too