Linux Warm Boot?

[Håkan Persson]

Hi!

I am interested in making it possible to "warm boot" a Linux kernel.
I would like start off booting on a USB-stick (which I have succeeded in 
doing), perform some checks and then completely replacing the running 
system with another system located on a hard disk, just like it would 
have booted in the first place. I just can't reboot the system since it 
is set to boot on the USB-stick first.

Any suggestions?

Thanks,
Håkan