Initrd

Hello,

I am using linux 2.6.26 on a powerpc board. I would like to use a initrd. So
I set the initrd option in the kernel. But when I boot Linux, it crashes
before  start_kernel(). And after the configuration of the MMU. The last
words of the prompt are :
Probing machine type ...
  MPC7448 on IAD68 ... match !
id mach(): done
MMU:enter
MMU:hw init
hash:enter
hash:find piece
hash:patch
hash:done
MMU:mapin
MMU:setio
MMU:exi

Can you help me ?