beagleboard boot options

I need some help in understanding the beagleboard booting process.
Well it's a DevKit8000, just the same board but with ethernet support
(Davicom DM9000).
I got Angstrom running from SD-Card, but only if I press the boot-key
after reset.
I can set bootcmd and a bootargs so that kernel and ramdisk gets
loaded with tftp.
But after uncompressing the kernel nothing happens!
Looks like the kernel doesn't even get started.
I wonder why I have to press the button to get something running.
And what is the ramdisk for. Looks likes the beagleboard doesn't need
I also tried to load the root filesystem by nfs but as above nothing
without pressing the boot key.
And if I press it, it loads everything from the sd-card.
Here is my last attempt:
bootcmd=tftp 80300000 uImage;tftp 81600000 ramdisk.gz;bootm 80300000
bootargs==console=ttyS2,115200n8 noinitrd root=/dev/nfs rw
Help appreciated!

2010/9/7 Jörg Klein <>

But after uncompressing the kernel nothing happens!

It seems that the mach-id of uboot & kernel did not match.

What version & detail of your images? (uboot, xload, kernel)