I have 4 partition on 2Tb hard disk.
sda1 windows
sda2 data
sda3 linux
sda4 grub
boot from sda3 works well.
but failed booting from sda4
I see grub is support 2Tb harddisk. the grub partition is at the end of harddisk.
#### works well boot configuration###
root (hd0,2)
setup (hd0)
#### failed boot configration #####
root (hd0,3)
setup (dh0)