[Buildroot] Unable to boot via initrd

[Bart J. Smit]

Another buildroot newbie looking at this. I'm looking to create a PXE boot for generic x86.

I've created the initial ramdisk with:
 mount -o loop rootfs.ext2 ../initrd
 cd ../initrd
 find . | cpio -o -H newc | gzip > ../initrd.img

When I PXE boot the client, it gets to:
  VFS Cannot open root device, please append a correct root= boot option; here are the available partitions
  Kernel panic - not syncing: VFS; Unable to mount root fs on unknown-block(2,0)

>From what I can google, this seems to be a popular use for small builds such as buildroot. Do any of the gurus on this list have a recipe to achieve a PXE boot image?

Thanks,

Bart...