I went over a number of the GRUB instructions. The kernel starts loading and stops with kernel panic.
VFS: Cannot open root device "sdb2" or unknown-block(0,0)
Please append a correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
I am quite certain that the root is sdb2 which is the Linux partition. I verified it using fdisk.
What could be going wrong?