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Re: root file system installation - unique question

On 2007-08-21 06:57 -0700, tsnider wrote:
> This isn't the typical installation question. I already have a custom Linux
> kernel (based on open embedded vanilla) for my embedded system that needs to
> stay in place. However the root file system isn't hardware  / application
> sensitive. I'd like to use Debian for the rfs. I've extracted the minimal
> image from initrd. After reading the Debian installation manual I'm still
> not clear on what script or where the Debian installation process is
> started. The system doesn't have a cd so it can't start normally. I have an
> installation cd image accessible to the system. So I'd like to find the
> "magic" starting point that kicks off the installation process after my
> kernel (not Debian) is up and running. 

I'm not sure about how to do what you want but I am doing the same
sort of thing (with balloonboard) - i.e. our own kernel.org-based
kernel plus normal debian rootfs. I use debootstrap to get the initial
image onto the machine. debootstrap --foreign --arch arm for 1st
stage, then a little script to set a few vital files (securetty,
create some missing /dev files, fstab, modules) so the result will
boot enough to run debootstrap/debootstrap --second-stage 

In fact whilst this works it is slow in flash so I changed to not
actually mounting the 1st stage debootstrap but instead chroot into the
unpacked image on media then run the 2nd stage, and copy the result
into the rootfs. (booting enough to chroot is done using a
buildroot-constructed kernel+initrd ram image which serves as general
rescue image - your platform may not have space for this little extra).

Once you reboot into the configured root image you are running
standard debian and can apt-get whatever you need if you can configure
a network connection. 

This is all a bit hacky and some extra support in debootstrap for a
sort of 'post-install' script and device tables would be good. I
started this at debconf but didn't get very far as writing in pure
shell is quite labour-intensive.

If you want to crib my (horrible) make system look at 
svn list svn://balloonboard.org/balloon/trunk/
details of the above hackery are in 
trunk/rootfs/debian/Makefile and rootfs-config or

If anyone knows less-horrible ways of organising some of this stuff
I'd like to hear about it. 

Principal hats:  Balloonz - Toby Churchill - Aleph One - Debian

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