Re: [gentoo-amd64] boot Gentoo from USB key

[Kyle Liddell <kyle@foobox.homelinux.net>]

On Wed, Apr 30, 2008 at 08:43:53AM +0200, Raffaele BELARDI wrote:
> In the process of building an amd64 diskless box, I am trying to make a
> bootable USB key with no success up to now.
> 
> The kernel starts to load, but panics because it is unable to find the
> root partition. When it stops it shows the available partitions, these
> include all the hard disk partitions but no USB key partition. In fact,
> if I omit the 'root' parameter from the grub shell the boot works fine
> but it uses the hard disk root partition instead of the USB one.
> 
> >From the log on the screen the USB controller seems correctly detected,
> so I don't understand why it is not finding the root. While writing this
> one idea comes to my mind, maybe it is failing because I attach the key
> to a SDC/MMC/USB card reader? This evening I'll try to plug it into a
> different USB slot.
> 

Try adding the rootdelay=N kernel option.  When I was running a laptop from a USB device, rootdelay=12 was the minimum that would always work.  It takes a while to detect all the available USB devices, and rootdelay makes the kernel wait N seconds before trying to mount the given root device.
(Also, be sure you have usb_storage, etc compiled in.)

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