[Buildroot] initramfs doesn't get linked into kernel

[Adam Nielsen]

Hi all,

I'm trying to figure out how to get the initramfs image linked in to my kernel 
zImage.  I have selected BR2_TARGET_ROOTFS_INITRAMFS (the only option I can 
find in the menuconfig containing 'initramfs') but nothing gets linked in to 
my kernel.

I am using a custom kernel config, and I tried putting the filename of the 
buildroot-generated .cpio image in as CONFIG_INITRAMFS_SOURCE which linked in 
successfully, but then it won't boot as it appears you are supposed to put an 
initramfs configuration filename here instead.

Is it correct that I have to manually put something into 
CONFIG_INITRAMFS_SOURCE?  If so, what should I place here to use the rootfs 
generated by buildroot?

Many thanks,
Adam.