I patched S9RYD bash file from Jay lee's chrubuntu install script, where anyone could re-install a broken chrubuntu installation.

s9ryd_reinstall

#!/bin/bash
#
# Script to install Ubuntu on Chromebooks
# 
# Copyright 2012-2013 Jay Lee
# small Patch by Tiana R. 08/2013
#
# here would be nice to have some license - BSD one maybe
#

# make sure that we have root permissions
if [[ $EUID -ne 0 ]]; then
   echo "This script must be run as root" 1>&2
   exit 1
fi

if [ ! $BASH_VERSION ];then
  echo "This script must be run in bash"
  exit 1
fi

# fw_type will always be developer for Mario.
# Alex and ZGB need the developer BIOS installed though.
fw_type="`crossystem mainfw_type`"
if [ ! "$fw_type" = "developer" ]
  then
    echo -e "\nYou're Chromebook is not running a developer BIOS!"
    echo -e "You need to run:"
    echo -e ""
    echo -e "sudo chromeos-firmwareupdate --mode=todev"
    echo -e ""
    echo -e "and then re-run this script."
    exit 
fi

powerd_status="`initctl status powerd`"
if [ ! "$powerd_status" = "powerd stop/waiting" ]
then
  echo -e "Stopping powerd to keep display from timing out..."
  initctl stop powerd
fi

setterm -blank 0

if [ "$3" != "" ]; then
  target_disk=$3
  echo "Got ${target_disk} as target drive"
  echo ""
  echo "WARNING! All data on this device (if you run this on your hdd /dev/sda) it will be wiped out! It is meant for external memory cards that do not contain the chromeos Filesystem.  Continue at your own risk!"
  echo ""
  read -p "Press [Enter] to install ChrUbuntu on ${target_disk} or CTRL+C to quit"

  ext_size="`blockdev --getsz ${target_disk}`"
  aroot_size=$((ext_size - 65600 - 33))
  parted --script ${target_disk} "mktable gpt"
  cgpt create ${target_disk} 
  cgpt add -i 6 -b 64 -s 32768 -S 1 -P 5 -l KERN-A -t "kernel" ${target_disk}
  cgpt add -i 7 -b 65600 -s $aroot_size -l ROOT-A -t "rootfs" ${target_disk}
  sync
  blockdev --rereadpt ${target_disk}
  partprobe ${target_disk}
  crossystem dev_boot_usb=1
else
  target_disk="`rootdev -d -s`"
  # Do partitioning (if we haven't already)
  ckern_size="`cgpt show -i 6 -n -s -q ${target_disk}`"
  croot_size="`cgpt show -i 7 -n -s -q ${target_disk}`"
  state_size="`cgpt show -i 1 -n -s -q ${target_disk}`"
  stateful_start="`cgpt show -i 1 -n -b -q ${target_disk}`"
  broot_start="`cgpt show -i 5 -n -b -q ${target_disk}`"

  max_ubuntu_size=$((($state_size)/1024/1024/2))
  rec_ubuntu_size=$(($max_ubuntu_size - 1))
  # If KERN-C and ROOT-C are one, we partition, otherwise assume they're what they need to be...
  if [ "$ckern_size" =  "1" -o "$croot_size" = "1" -o "$1" = "repart" ]
  then
    while :
    do
      read -p "Enter the size in gigabytes you want to reserve for Ubuntu. Acceptable range is 5 to $max_ubuntu_size  but $rec_ubuntu_size is the recommended maximum: " ubuntu_size
      if [ ! $ubuntu_size -ne -1 2>/dev/null ]
      then
        echo -e "\n\nNumbers only please...\n\n"
        continue
      fi
      if [ $ubuntu_size -lt 0 -o $ubuntu_size -gt $max_ubuntu_size ]
      then
        echo -e "\n\nThat number is out of range. Enter a number 5 through $max_ubuntu_size\n\n"
        continue
      fi
      break
    done
    # We've got our size in GB for ROOT-C so do the math...

    if [ "$ubuntu_size" = "0" ]
    then
      rootc_size=1
      kernc_size=1
    else
      #calculate sector size for rootc
      rootc_size=$(($ubuntu_size*1024*1024*2))

      #kernc is always 16mb
      kernc_size=32768
    fi

    #new stateful size with rootc and kernc subtracted from original
    stateful_size=$((($state_size) - $rootc_size - $kernc_size))

    #start kernc at stateful start plus stateful size
    kernc_start=$(($stateful_start + $stateful_size))

    #start rootc at kernc start plus kernc size
    rootc_start=$(($kernc_start + $kernc_size))

    #Do the real work
    
    echo -e "\n\nModifying partition table to make room for Ubuntu." 
    echo -e "Your Chromebook will reboot, wipe your data and then"
    echo -e "you should re-run this script..."
    umount -f /mnt/stateful_partition
    
    # kill old parts
    cgpt add -i 1 -t unused ${target_disk}
    cgpt add -i 6 -t unused ${target_disk}
    cgpt add -i 7 -t unused ${target_disk}
    
    # stateful first
    cgpt add -i 1 -b $stateful_start -s $stateful_size -t data -l STATE ${target_disk}

    # now kernc
    cgpt add -i 6 -b $kernc_start -s $kernc_size -t kernel -l KERN-C ${target_disk}

    # finally rootc
    cgpt add -i 7 -b $rootc_start -s $rootc_size -t rootfs -l ROOT-C ${target_disk}

    reboot
    exit
  fi
fi

# hwid lets us know if this is a Mario (Cr-48), Alex (Samsung Series 5), ZGB (Acer), etc
hwid="`crossystem hwid`"

chromebook_arch="`uname -m`"

ubuntu_metapackage=${1:-default}

latest_ubuntu=`wget --quiet -O - http://changelogs.ubuntu.com/meta-release | grep "^Version: " | tail -1 | sed -r 's/^Version: ([^ ]+)( LTS)?$/\1/'`
ubuntu_version=${2:-$latest_ubuntu}

if [ "$ubuntu_version" = "lts" ]
then
  ubuntu_version=`wget --quiet -O - http://changelogs.ubuntu.com/meta-release | grep "^Version:" | grep "LTS" | tail -1 | sed -r 's/^Version: ([^ ]+)( LTS)?$/\1/'`
elif [ "$ubuntu_version" = "latest" ]
then
  ubuntu_version=$latest_ubuntu
fi

if [ "$chromebook_arch" = "x86_64" ]
then
  ubuntu_arch="amd64"
  if [ "$ubuntu_metapackage" = "default" ]
  then
    ubuntu_metapackage="ubuntu-desktop"
  fi
elif [ "$chromebook_arch" = "i686" ]
then
  ubuntu_arch="i386"
  if [ "$ubuntu_metapackage" = "default" ]
  then
    ubuntu_metapackage="ubuntu-desktop"
  fi
elif [ "$chromebook_arch" = "armv7l" ]
then
  ubuntu_arch="armhf"
  if [ "$ubuntu_metapackage" = "default" ]
  then
    ubuntu_metapackage="xubuntu-desktop"
  fi
else
  echo -e "Error: This script doesn't know how to install ChrUbuntu on $chromebook_arch"
  exit
fi

echo -e "\nChrome device model is: $hwid\n"

echo -e "Installing Ubuntu ${ubuntu_version} with metapackage ${ubuntu_metapackage}\n"

echo -e "Kernel Arch is: $chromebook_arch  Installing Ubuntu Arch: $ubuntu_arch\n"

read -p "Press [Enter] to continue..."

if [ ! -d /mnt/stateful_partition/ubuntu ]
then
  mkdir /mnt/stateful_partition/ubuntu
fi

cd /mnt/stateful_partition/ubuntu

if [[ "${target_disk}" =~ "mmcblk" ]]
then
  target_rootfs="${target_disk}p7"
  target_kern="${target_disk}p6"
else
  target_rootfs="${target_disk}7"
  target_kern="${target_disk}6"
fi

echo "Target Kernel Partition: $target_kern  Target Root FS: ${target_rootfs}"

if mount|grep ${target_rootfs}
then
  echo "Refusing to continue since ${target_rootfs} is formatted and mounted. Try rebooting"
  exit 
fi

mkfs.ext4 ${target_rootfs}

if [ ! -d /tmp/urfs ]
then
  mkdir /tmp/urfs
fi
mount -t ext4 ${target_rootfs} /tmp/urfs

tar_file="http://cdimage.ubuntu.com/ubuntu-core/releases/$ubuntu_version/release/ubuntu-core-$ubuntu_version-core-$ubuntu_arch.tar.gz"
if [ $ubuntu_version = "dev" ]
then
  ubuntu_codename=`wget --quiet -O - http://changelogs.ubuntu.com/meta-release-development | grep "^Dist: " | tail -1 | sed -r 's/^Dist: (.*)$/\1/'`
  ubuntu_version=`wget --quiet -O - http://changelogs.ubuntu.com/meta-release-development | grep "^Version:" | tail -1 | sed -r 's/^Version: ([^ ]+)( LTS)?$/\1/'`
  tar_file="http://cdimage.ubuntu.com/ubuntu-core/daily/current/$ubuntu_codename-core-$ubuntu_arch.tar.gz"
fi

# convert $ubuntu_version from 13.04 to 1304
ubuntu_version=`echo $ubuntu_version | sed -e 's/\.//g'`

wget -O - $tar_file | tar xzp -C /tmp/urfs/

mount -o bind /proc /tmp/urfs/proc
mount -o bind /dev /tmp/urfs/dev
mount -o bind /dev/pts /tmp/urfs/dev/pts
mount -o bind /sys /tmp/urfs/sys

cp /etc/resolv.conf /tmp/urfs/etc/
echo chrubuntu > /tmp/urfs/etc/hostname

cr_install="wget -q -O - https://dl-ssl.google.com/linux/linux_signing_key.pub | sudo apt-key add -
add-apt-repository \"deb http://dl.google.com/linux/chrome/deb/ stable main\"
apt-get update
apt-get -y install google-chrome-stable"
if [ $ubuntu_arch = 'armhf' ]
then
  cr_install='apt-get -y install chromium-browser'
fi

add_apt_repository_package='software-properties-common'
if [ $ubuntu_version -lt 1210 ]
then
  add_apt_repository_package='python-software-properties'
fi

echo -e "useradd -m user
echo user | echo user:user | chpasswd
adduser user adm
adduser user sudo
apt-get -y update
apt-get -y dist-upgrade
apt-get -y install ubuntu-minimal
apt-get -y install wget
apt-get -y install $add_apt_repository_package
add-apt-repository main
add-apt-repository universe
add-apt-repository restricted
add-apt-repository multiverse 
apt-get update
apt-get -y install libnss-myhostname $ubuntu_metapackage
$cr_install
if [ -f /usr/lib/lightdm/lightdm-set-defaults ]
then
  /usr/lib/lightdm/lightdm-set-defaults --autologin user
fi" > /tmp/urfs/install-ubuntu.sh

chmod a+x /tmp/urfs/install-ubuntu.sh
chroot /tmp/urfs /bin/bash -c /install-ubuntu.sh
rm /tmp/urfs/install-ubuntu.sh

# Keep CrOS partitions from showing/mounting in Ubuntu
udev_target=${target_disk:5}
echo -e "KERNEL==\"$udev_target1\" ENV{UDISKS_IGNORE}=\"1\"
KERNEL==\"$udev_target3\" ENV{UDISKS_IGNORE}=\"1\"
KERNEL==\"$udev_target5\" ENV{UDISKS_IGNORE}=\"1\"
KERNEL==\"$udev_target8\" ENV{UDISKS_IGNORE}=\"1\"" > /tmp/urfs/etc/udev/rules.d/99-hide-disks.rules

if [ $ubuntu_version -lt 1304 ] # pre-raring
then
	if [ -f /usr/bin/old_bins/cgpt ]
	then
		cp -p /usr/bin/old_bins/cgpt /tmp/urfs/usr/bin/
	else
		cp -p /usr/bin/cgpt /tmp/urfs/usr/bin/
	fi
else
	echo "apt-get -y --force-yes install cgpt vboot-kernel-utils" >/tmp/urfs/install-ubuntu.sh

	if [ $ubuntu_arch = "armhf" ]
	then
		cat > /tmp/urfs/usr/share/X11/xorg.conf.d/exynos5.conf <<EOZ
Section "Device"
        Identifier      "Mali FBDEV"
        Driver          "armsoc"
        Option          "fbdev"                 "/dev/fb0"
        Option          "Fimg2DExa"             "false"
        Option          "DRI2"                  "true"
        Option          "DRI2_PAGE_FLIP"        "false"
        Option          "DRI2_WAIT_VSYNC"       "true"
#       Option          "Fimg2DExaSolid"        "false"
#       Option          "Fimg2DExaCopy"         "false"
#       Option          "Fimg2DExaComposite"    "false"
        Option          "SWcursorLCD"           "false"
EndSection
Section "Screen"
        Identifier      "DefaultScreen"
        Device          "Mali FBDEV"
        DefaultDepth    24
EndSection
EOZ
                cat > /tmp/urfs/usr/share/X11/xorg.conf.d/touchpad.conf <<EOZ
Section "InputClass"
        Identifier "touchpad"
        MatchIsTouchpad "on"
        Option "FingerHigh" "5"
        Option "FingerLow" "5"
EndSection
EOZ
		echo "apt-get -y install --no-install-recommends linux-image-chromebook xserver-xorg-video-armsoc" >>/tmp/urfs/install-ubuntu.sh

		# valid for raring, so far also for saucy but will change
		kernel=/tmp/urfs/boot/vmlinuz-3.4.0-5-chromebook
	fi

	chmod a+x /tmp/urfs/install-ubuntu.sh
	chroot /tmp/urfs /bin/bash -c /install-ubuntu.sh
	rm /tmp/urfs/install-ubuntu.sh
fi

# we do not have kernel for x86 chromebooks in archive at all
# and ARM one only in 13.04 and later
if [ $ubuntu_arch != "armhf" -o $ubuntu_version -lt 1304 ]
then
	KERN_VER=`uname -r`
	mkdir -p /tmp/urfs/lib/modules/$KERN_VER/
	cp -ar /lib/modules/$KERN_VER/* /tmp/urfs/lib/modules/$KERN_VER/
	if [ ! -d /tmp/urfs/lib/firmware/ ]
	then
	  mkdir /tmp/urfs/lib/firmware/
	fi
	cp -ar /lib/firmware/* /tmp/urfs/lib/firmware/

	kernel=/boot/vmlinuz-`uname -r`
fi

echo "console=tty1 debug verbose root=${target_rootfs} rootwait rw lsm.module_locking=0" > kernel-config
vbutil_arch="x86"
if [ $ubuntu_arch = "armhf" ]
then
  vbutil_arch="arm"
fi
vbutil_kernel --pack newkern \
    --keyblock /usr/share/vboot/devkeys/kernel.keyblock \
    --version 1 \
    --signprivate /usr/share/vboot/devkeys/kernel_data_key.vbprivk \
    --config kernel-config \
    --vmlinuz $kernel \
    --arch $vbutil_arch

dd if=newkern of=${target_kern} bs=4M

#Set Ubuntu kernel partition as top priority for next boot (and next boot only)
cgpt add -i 6 -P 5 -T 1 ${target_disk}

echo -e "

Installation seems to be complete. If ChrUbuntu fails when you reboot,
power off your Chrome OS device and then turn it back on. You'll be back
in Chrome OS. If you're happy with ChrUbuntu when you reboot be sure to run:

sudo cgpt add -i 6 -P 5 -S 1 ${target_disk}

To make it the default boot option. The ChrUbuntu login is:

Username:  user
Password:  user

We're now ready to start ChrUbuntu!
"

read -p "Press [Enter] to reboot..."

reboot