Boot linux from cramfs on USB

[Sascha Hauer]

On Mon, Apr 02, 2012 at 03:58:49PM +0200, Jakob Malm wrote:
> Hi,
> 
> How would I boot a linux system in a cramfs image on USB? I don't seem
> to be able to mount such an image:
> 
> barebox:/ usb
> USB: scanning bus for devices...
> Bus 001 Device 002: ID 0dd8:1728 Flash Drive
> Using index 1 for the new disk
> Bus 001 Device 001: ID 0000:0000 EHCI Host Controller
> 2 USB Device(s) found
> barebox:/ mkdir /usb
> barebox:/ mount /dev/disk1.0 fat /usb
> barebox:/ mkdir /cramfs
> barebox:/ mount /usb/rootfs.cramfs cramfs /cramfs
> mount: Invalid argument
> 
> Is it not possible to mount a cramfs image file?

cramfs currently has the limitation that it can only mount
files which are memory mappable (that is for example nor flash).
I never fixed this due to the lack of interest for cramfs.

That said, your setup seems a bit crazy. What is inside your cramfs? The
kernel? You should rather put your kernel into a plain partition on the
USB disk. Or do you only have your rootfs inside the cramfs? I rather
recommend ext2 or ext3 for this.

Sascha


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