Uboot for GuruPlug

GuruPlug, GuruPlug Server Plus

Here's how to allow your GuruPlug to boot from a USB drive.
You'll need an access to the serial console to achieve this, the JTAG module is OK.

• To connect to the bootloader, proceed exactly like for the Sheevaplug: http://wiki.amahi.org/index.php/Marvell_Plug_Computer

• Reset the GuruPlug.
• At the terminal, press enter a couple of seconds after boot to prevent it from booting using the onboard flash (Ubuntu). You should end up with a prompt.
• Some version of the GuruPlug have been shipped with a uboot that does not support Booting from USB, ESATA or SD-Card. If this is your case, then you have to upgrade uboot. To do this, the best howto I found is this : http://oinkzwurgl.org/guruplug_uboot

• There are some commands you need to run to make it permanently boot from the USB port (NOTE: this step is only necessary once):

setenv mainlineLinux yes
setenv x_bootargs_root 'root=/dev/sdb1 rootdelay=15'
setenv x_bootcmd_kernel 'ext2load usb 1:1 0x6400000 /boot/uImage'
saveenv

While still under the bootloader , check your environment with printenv. It must look like this:

GuruPlug>> printenv
bootcmd=${x_bootcmd_usb}; ${x_bootcmd_kernel}; setenv bootargs ${x_bootargs} ${x_bootargs_root}; bootm 0x6400000;
bootdelay=3
baudrate=115200
x_bootcmd_usb=usb start
ethact=egiga0
x_bootcmd_kernel=ext2load usb 1:1 0x6400000 /boot/uImage
arcNumber=2653
mainlineLinux=yes
x_bootargs_root=root=/dev/sdb1 rootdelay=15
x_bootargs=console=ttyS0,115200
stdin=serial
stdout=serial
stderr=serial