While booting Android on a Pandaboard, I am partitioning the SD card into two partitions, boot and root. They contain different filesystems. Why does the boot partition need to be vfat, while the rootfs needs to be ext3 or ext4?
I don't know the Pandaboard SoC, but I think I know the answer.
VFAT is an easy enough file system for even a majority of simple devices (think MP3 players, satnavs, DVD players, etc) to understand, presumably including the Pandaboard's bootloader, so it's a natural choice for a boot partition.
A Linux system, on the other hand, needs a filesystem with features such as permissions and device files, therefore an ext3/ext4 file system is used.