Is it possible to netboot a FreeRunner?

David Pottage david at
Sun Aug 31 23:06:17 CEST 2008

On Sunday 31 August 2008 16:34:35 Jeff Sadowski wrote:
> You would probably  need a driver built into uboot to recognize a usb
> network device or maybe a way in uboot to setup wifi. I know my avaya
> wireless phones look for new images on my tftp server when they boot.
> Maybe if there was a way to replace a live kernel that might work for
> you?

I think that would be the way to achieve a net boot, by faking it via the 
standard kernel.

To do this we have a menu entry for netboot, but what it actually does is 
starts the normal kernel in flash, passing a netboot command line option. The 
kernel boots and once it has loaded the usb-net drivers and suchlike, but 
before it starts userspace, it downloads the requested kernel over the usb 
network and runs it via kexec.

If that first stage boot to get the usb-net drivers is fast, then it will 
create the illusion of having netboot support, without the need to add 
support for usb-networking and all sorts of other tricky features to U-boot.

Of course it would be necessary to add this netboot support to the kernel, but 
I would imagine that it would be much easier, as it is only one feature into 
a  system with plenty of support functions for memory, I/O etc, rather than 
many into a system without.

In order for that feature to work universally, it would have to be in every 
kernel that is likely to be flashed into a freerunner, and the only way that 
will happen is if the developer is able to persuade Linus and the rest of the 
kernel people that it is a feature worthy of Linux. (They may take the view 
that it is an ugly hack and that sort of thing ought to be in the BIOS/U-Boot 

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