Re: looking for a model for building CRAMFS(?)-based system

Hi,

On Wed, 16 Mar 2005 11:33:39 -0500 (EST), Robert P. J. Day
[off-list ref] wrote:

  currently, the system i've built for our 850 board incorporates

        - boot loader (sadly, not u-boot, but i'm working on it)
        - standard zImage.initrd.bin kernel+initrd image
        ... mountable JFFS2 filesystem with persistent stuff ...

  obviously, with this layout, it's kind of a nuisance to update
anything individually in the initrd portion of the system, so i'd like
to at least experiment with a layout that has separate

        - boot loader (ideally, u-boot)
        - kernel image
        - updateable (normally mounted read-only?) root filesystem
        ... rest of stuff the same ...

I'm using separate MTD partitions for bootloader, device parameters,
zImage, initrd and persistent storage.

When updating the initrd, the only thing necessary is a
eraseall /dev/mtdX
cat initrd.gz > /dev/mtdX

When booting the kernel, you need something like this in the commandline:
root=/dev/mtdblockX prompt_ramdisk=0 load_ramdisk=1 ramdisk_size=8192

This is bootloader independent, of course.

HTH,
Patrick