This page describes how to roll an OAMP4 image from scratch, similar (but not identical) to the released omap4 images ubuntu provides.

You should have a fast armel machine for building the root filesystem. The subsequent image build that gets created out of the resulting livefs files can then happen on an i386 machine.

== Rolling the LiveFS ==

On an armel system do the following:

sudo apt-get install livecd-rootfs

sudo /usr/sbin/livecd.sh -somap4 -dmaverick -fext3 -aarmel ubuntu-netbook

This will create an ext3 filesystem file, an initrd and a kernel together with a manifest file that describes the contents of the filesystem

== Building the actual image ==

For wrapping together the partitioned preinstalled image you need some script similar to the one below.

{{{
##!/bin/bash
#
# this script creates an image to write to a SD card with a PC partition table;
# the first partition is the vfat passed as $3 ($IMAGE) and contains the
# root fs.

# OMAP3 requires very specific CHS partitioning that can't easy be done with parted
# so we'll use sfdisk to properly make the necessary partition layout

# globals (please adjust or autodetect or whatever (based on SUBARCH))
# note thses  paths point to manually unpacked .debs on my disk atm

set -e

file_length() {
    stat -c %s "$1"
}


xloader_package="x-loader-omap4"
path_to_xloader="usr/lib/x-loader-omap4/MLO"

uboot_package="u-boot-linaro-omap4-panda"
path_to_uboot="usr/lib/u-boot/omap4_panda/u-boot.bin"

v_opts="vram=32M"
board_opts="mem=463M"

log "Extracting bootloader from main archive"
extract_file_from_package $xloader_package $path_to_xloader "MLO"
extract_file_from_package $uboot_package $path_to_uboot "u-boot.bin"

uboot_kernel="uImage"
uboot_initrd="uInitrd"
uboot_kernel_addr="0x80000000"
uboot_ramdisk_addr="0x81600000"
uboot_script_addr="0x1000"
uboot_script_text="$CDDIR/boot.scr.in"
uboot_script_image="$CDDIR/boot.scr"

uboot_desc="Ubuntu Preinstalled Image"
uboot_input_kernel="$PREINSTALLEDIMAGES/$FULLARCH.kernel-$SUBARCH"
uboot_input_initrd="$PREINSTALLEDIMAGES/$FULLARCH.initrd-$SUBARCH"
uboot_extra_cmdline=" root=/dev/mmcblk0p2 fixrtc"

EXT3=$IMAGE.rootfs
MTOOLSRC=$IMAGE.mtoolsrc

# Turn our kernel and initrd into a uImage and uInitrd
log "Calling uboot-mkimage on kernel and ramdisk"

rm -f $uboot_kernel $uboot_initrd
mkimage -A arm -O linux -T kernel -C none -a 0x80008000 -e 0x80008000 -n "Ubuntu Kernel" -d "$uboot_input_kernel" "$uboot_kernel"
mkimage -A arm -O linux -T ramdisk -C gzip -a 0x0 -e 0x0 -n "Ubuntu Initrd" -d "$uboot_input_initrd" "$uboot_initrd"


# here we will need to create boot.scr and mcopy it too
log "Generating boot.scr"
cat >"$uboot_script_text" <<EOF
    fatload mmc 0:1 $uboot_kernel_addr $uboot_kernel
    fatload mmc 0:1 $uboot_ramdisk_addr $uboot_initrd
    setenv bootargs $v_opts $board_opts $DEFAULT_PRESEED $uboot_extra_cmdline
    bootm $uboot_kernel_addr $uboot_ramdisk_addr
EOF

mkimage -A arm -T script -C none -n "Ubuntu boot script" -d "$uboot_script_text" "$uboot_script_image"
rm -f "$uboot_script_text"

# Move the ext3 filesystem out of the way
mv $IMAGE $EXT3

# mtools sanity checks are getting in the way, so we need to turn its brain off
cat > $MTOOLSRC <<EOF
mtools_skip_check=1
EOF

export MTOOLSRC

# we leave 72MB for the vfat that carries u-boot, MLO, uImage,
# uInitrd and boot.scr
BOOT_SIZE="$((72 * 1024 * 1024))"

IMAGE_SIZE="$(file_length "$EXT3")"
IMG_SIZE_BLOCKS="$((($BOOT_SIZE + $IMAGE_SIZE + 512 - 1) / 512))"

dd if=/dev/zero of="$IMAGE" bs=512 count=0 seek="$IMG_SIZE_BLOCKS" >/dev/null 2>&1

TRG_SIZE="$(file_length "$IMAGE")"
CYLINDERS=`echo $TRG_SIZE/255/63/512 | bc`

{
    echo ,9,0x0C,*
    echo ,,,-
} | sfdisk -D -H 255 -S 63 -C $CYLINDERS $IMAGE >/dev/null 2>&1

VATSTART=$(parted $IMAGE unit B print|grep "^ 1"|awk '{print $2}')
VATSIZE=$(LANG=C fdisk -l ${IMAGE} 2>/dev/null|grep W95 |awk '{print $5}')

mkdosfs -F 32 -C $IMAGE.vfat ${VATSIZE} >/dev/null 2>&1
mcopy -i $IMAGE.vfat MLO ::MLO
mcopy -i $IMAGE.vfat u-boot.bin ::u-boot.bin
mcopy -i $IMAGE.vfat $uboot_kernel ::uImage
mcopy -i $IMAGE.vfat $uboot_initrd ::uInitrd
mcopy -i $IMAGE.vfat $uboot_script_image ::boot.scr

# now put the whole vfat into the first partition
dd conv=notrunc bs="${VATSTART%B}" if=$IMAGE.vfat of="$IMAGE" seek=1 >/dev/null 2>&1
rm $IMAGE.vfat

# put ext3 content into the second partition
EXT3START=$(parted $IMAGE unit B print|grep "^ 2"|awk '{print $2}')
dd conv=notrunc bs="${EXT3START%B}" if=$IMAGE.rootfs of="$IMAGE" seek=1 >/dev/null 2>&1

# Cleanup
rm -f "$IMAGE.rootfs" "$IMAGE.vfat" "$IMAGE.mtoolsrc" MLO u-boot.bin uImage uInitrd
}}}