rtomj / 9frontPi

Creating a 9front Pi Img (Tested with a Raspberry Pi Zero)
 
NOTE: The latest 9front release has an updated guide on building an sdcard img (http://fqa.9front.org/appendixj.html)

The current img (9front-pi-3125.9fcca5b8ac11.img) will not boot unless you overwrite 
the files on the FAT partition with the updated pi firmware (https://github.com/raspberrypi/firmware).
This will boot, however the resulting img is very outdated.

First, create the img file (adjust count for sd card size):
dd if=/dev/zero of=9frontPi.img count=13000000

Create a small FAT16 partition:
fdisk 9frontPi.img
n (new part)
p (primary)
sectors= +70M
t (change type)
hex code = 6 (FAT16)

Use the rest of the img for a Plan9 partition:
n
e (extended)
sectors (use the rest of the img)
t
hex code = 39 (Plan9)
w (write)
q (quit)

Using QEMU, boot the 9front.iso using the img as the drive:

qemu-system-x86_64 -cpu host -enable-kvm -m 1024 \
 -net nic,model=virtio,macaddr=52:54:00:00:EE:03 -net user \
 -device virtio-scsi-pci,id=scsi \
 -drive if=none,id=vd0,file=9frontPi.img -device scsi-hd,drive=vd0 \
 -drive if=none,id=vd1,file=9front.iso -device scsi-cd,drive=vd1,bootindex=0

Install 9front to the img. Use hjfs and use an appropriate ram cache for
your pi model. Install 9fat and make sure it's marked as active and installed to
the master boot record (You will need this in order to boot into the img file. After
the img is burned to the card, the Pi will use the FAT partition for booting).
Complete the installation.

Boot 9frontPi.img:

qemu-system-x86_64 -cpu host -enable-kvm -m 1024 \
 -net nic,model=virtio,macaddr=52:54:00:00:EE:03 -net user \
 -device virtio-scsi-pci,id=scsi \
 -drive if=none,id=vd0,file=9frontPi.img -device scsi-hd,drive=vd0

You will have to compile everything for ARM. Create any missing directories:
cd /
. /sys/lib/rootstub

Compile everything:
cd /sys/src
objtype=arm mk install

Compile the kernel:
cd /sys/src/9/bcm
mk install && mk install 'CONF=picpuf'

Initialize the FAT partition:
disk/fdisk -d /dev/sd00/dos

Mount it:
dossrv -f /dev/sd00/dos
mount -c /srv/dos /n/rpi /dev/sd00/dos

Copy the kernels over:
cp /arm/9pif/ /arm/9picpuf /n/rpi

Download the updated rpi firmware and boot files and copy them over to the
FAT partition. You can mount the FAT partition after you burn the img to the sdcard
and copy them later if you are unable to do so.

Unmount the FAT partition:
umount /n/rpi
rm -f /srv/dos

Bring the system to a halt and exit QEMU. Now burn the img to the sd card:
dd bs=4M if=9frontPi.img of=/dev/sdb conv=fsync status=progress

If you did not copy the firmware and boot files earlier, mount the FAT partition
and copy them over. You should now be able to boot the img on the pi.