Thank you kindly Ash and Tyler for your input. Before diving in does anyone
want to hazard a guess on how much work will be required to get the MLO on
NAND to launch U-Boot and then the Kernel from MMC3?
I'll report back if I'm successful or stuck ;-)
On Sat, Jul 7, 2012 at 2:44 PM, Ash Charles <ashcharles@...> wrote:
> MMC3 is not, strictly speaking, a 'bootable' interface. This ends up
> meaning that the processor can't boot from an MLO file on this
> interface. With some work, I suspect an MLO on NAND or another
> bootable interface could be taught to find code on MMC3 at which point
> Tyler's instructions look good.
> On Sat, Jul 7, 2012 at 9:57 AM, Tyler Jones <tylerjones64@...>
> > I believe this is possible but have never tried it.
> > 1. Create a bootable sd card
> > 2. You need to make a u-boot script
> > 3. Create a file called bootcmd, and place U-Boot commands in there like
> > script file. For example:
> > setenv bootargs 'console=ttyO2,115200n8 root=/dev/mmcblk0p2 rw
> > rootfstype=ext3 rootwait'
> > mmc init
> > fatload mmc 0:1 0x80300000 uImage
> > bootm 0x80300000
> > boot
> > I have Highlighted the parts I think you will need to change, in case the
> > archive doesn't like the formatting they are:
> > 'mmcblk0p2' in setenv bootargs line (most likely the 0)
> > '0:1' in fatload line (most likely the 0)
> > 4. Use mkimage to create the boot.scr file. For example:
> > mkimage -A arm -O linux -T script -C none -a 0 -e 0 -n "Overo boot
> > -d bootcmd boot.scr
> > 5. Copy the resulting boot.scr to the fat16 partition on the SD card.
> > I have not tried this but I hope it gets you on the right track.
> > Please send an update on how this goes,
> > -Tyler Jones
> > On 7 July 2012 09:28, John Romeo <bluesmoke73@...> wrote:
> >> I have an expansion card that among other things connects a microSD slot
> >> to MMC3 on the J4 Gumstix header. Does anyone have an idea of how I
> >> boot from a filesystem on a card in that slot?