I have the Sprint Mogul 6800 (original rom), and it reads SDHC 8gb with no problems- out of the box... But after a little of research... everyone points out to cab SDHC777 will actually make your verizon vx6800 read 8gb (the post indicates 6gb- but others have said it can read 8 as well).... here is the link:
http://pdaphonehome.com/forums/666225-post41.html