Getting a Debian root filesystem on to a single-sided Balloon 3 board
Single-sided Balloon 3 boards do not have the communications connector fitted to the bottom of them, and early builds don't have USB host connections on the Pinko connector either. This means that the procedure described in BalloonSoftwareLoading isn't possible, because it assumes the ability to install from a USB drive.
Downloading the entire root filesystem over the serial port would take forever (for small values of forever) since the image is at least 60 megabytes. This means we've got to make do with the USB slave port, present on the JTAG connector, and some USB networking.
First, get the boot loader, FPGA image (if necessary), 'installer' image and kernel on to your board using bbl as described in BalloonSoftwareLoading.
Boot the board using 'boot flash' (which executes the 'recovery' kernel stored in NOR) and login as root (no password should be needed).
Get USB networking going using the instructions in USBNetworking. Recent versions of the Balloon 3 distribution (get the latest out of Subversion) have USB networking set up by default, so all you need to do is:
ifup usb0
Assuming you configured the host end correctly, you should now have network connectivity.
You can install the boot kernel on your board next. Mount the boot partition:
mount /mnt/boot/
You can use scp to copy stuff over to the balloon, but there are a few little wrinkles. The 'installer' image has dropbear in it, but prior to release 0.9 (April 2009) dropbear does not start automatically. You need to start it with
dropbear
The second wrinkle is that dropbear won't allow connections as root where root has no password (not unreasonable), but that's exactly how the initramfs is configured. So you need to
- edit /etc/passwd to add an 'x' in the second field of the first line, so it looks like this:
root:x:0:0:root:/root:/bin/sh
and
- b. do
passwd
to set a new root passwd, then exit and login again with the password. Now you should be able to ssh to the board with something like:
ssh root@10.0.0.2
Remember that this is a ram filesystem so if you reboot/power cycle you'll have to make these changes again.
If that works you can use scp to copy the kernel into the boot partition. The details of the command will vary depending on your networking setup, but it'll be something like
scp <user>@<hostname>:balloon3/build/kernel/zImageBoot /mnt/boot/zImage
Note that the kernel needs to be called zImage, otherwise the boot loader won't find it.
Note that this process is highly unreliable because the bootldr and kernel versions of yaffs do not quite match up. If you write a second copy as zImage2 then that often makes it work. The failure mode is that bootldr cannot read the kernel image corectly and thus fails to boot.
The next part requires you to have built the 'Stage 1' Debian root filesystem or the emdebian grip rootfilesystem. This is covered in SoftwareBuilding. These are debianstage1root.tgz and emdebianroot.tgz respectively in the directory build/rootfs.
Single-sided Balloon 3 boards generally only have 64MB of RAM, so the /tmp filesystem (which is in RAM) is not large enough to hold the Debian root filesystem tar file (~70Mb). Therefore we have to put it in the root filesystem itself, temporarily. The emdebian root filesystem will fit (~17Mb) so just copying it into ram works fine.
Mount the Balloon's NAND flash root filesystem
mount /mnt/root
and clear it
rm -rf /mnt/root/*
Debian rootfs
At the root prompt on the Balloon, use scp to copy the image. The details of the command will vary depending on your networking setup, but it'll be something like
scp <user>@<hostname>:balloon3/build/rootfs/debianstage1root.tgz /mnt/root
Unpack the filesystem image
cd /mnt/root tar xzvf debianstage1root.tgz
and delete the tarfile
rm debianstage1root.tgz
This root image is partly-configured, so it needs some Debian magic doing on it.
chroot /mnt/root /debootstrap/debootstrap --second-stage dpkg -i --force-confnew --force-overwrite --force-depends /var/cache/apt/archives/balloon3-config*.deb
That should leave you with a working root filesystem.
Emdebian rootfs
scp <user>@<hostname>:balloon3/build/rootfs/emdebianroot.tgz /mnt/root cd /mnt/root tar xzvf emdebianroot.tgz rm emdebianroot.tgz chroot /mnt/root dpkg --configure -a chmod 777 /
Packing up a configured filesystem
It is now possible to tar up the fully installed root filesystem. Note that you're still chroot'ed at this point.
tar cvzf debianrootfs.tgz *
To save this image on another machine, use scp, which first involves leaving the chroot environment
exit scp /mnt/root/debianrootfs.tgz <user>@<hostname>:<path>
Installing this filesystem on a Balloon board is then be simply a matter of copying it to /mnt/root using scp and untarring it.