The distro mkinird can reconstruct it containing your freshly built
modules (if any) and any other distro goo which needs to go in there.
/initrd-2.6.23.14-107.fc8.img doesn't come out of an rpm; its built by
an installer script when you install the kernel, and you can run the
same script on your kernels.
Does you use "make modules_install install" when you build the kernel?
It just does the right thing for me under F8, including rebuilding
initrd and updating grub.conf.
J
--