[Buildroot] Booting with ramdisk

[Guillaume Dargaud <dargaud@lpsc.in2p3.fr>]

Hello all,
I'm trying to do something very classic, but it doesn't seem to work and the more I read about it the more I'm confused 
by the amount of antiquated info and nearly-but-not-quite-so relevant info (like doing a temporary ramdisk before the 
real OS loads).

So I have a kernel and a buildroot-generated OS, currently on an NFS server. I boot with the following kernel parameters 
and everything goes fine:
console=ttyUL0,115200 rw root=/dev/nfs ip=bootp

Now I want to embed that OS in the kernel (no need for a network anymore as the kernel is on a flash mem). So I did the 
following:
- add ROOTFS CPIO to the buildroot options and make a new version
- point CONFIG_INITRAMFS_SOURCE to the resulting rootfs.cpio file
- change the kernel parameters to "console=ttyUL0,115200 root=/dev/ram" (that's in a dts file)

The kernel stops instantly without even a blip on the console. A debugger reveals that it stops at 0x401718... I have no 
idea what's going on at this stage.
-- 
Guillaume Dargaud
http://www.gdargaud.net/