Building an Edison image and changing the root partition size

22 November 2014

Update: As of February 2015, the newest version of the Edison image comes with a default root partition size of 1.4GB, which should be sufficiently large for most people. If you would still like to change the root partition size, these instructions should still work, but with a couple differences in the Linux source files, which are noted below.

Introduction

I’ve been using Edison for a few weeks now, and one of the issues I quickly ran into was not having enough space in the /dev/root partition. By default, the size is 512MB, which becomes very small once you start installing packages.

I started investigating on the forums and noticed this very helpful discussion on changing the partition’s size. After some trial and error, I was able to build a new Edison image with a larger partition for /dev/root, which I have summarized below. For reference, see this document for details on how to build an Edison image.

Before getting started, you also need a Linux machine. In my case, I created an Ubuntu 12.04 Vagrant VM on my Mac. The VM is provisioned with all the necessary packages to create an Edison image. It is also configured with 2GB of memory and with the ability to connect Edison via USB. You will also need about 30GB of disk space.

Getting the Linux source files

On your Linux machine, download the Edison Linux source files (.tgz). Unpack the .tgz file. If you saved it in the shared folder (if you are using the Vagrant VM), I suggest unpacking the file with the following command:

tar xvf edison-src.tgz -C ~

where edison-src.tgz is the name of the downloaded file. -C ~ unpacks it into the home directory of the VM. I ran into issues when building the image if the source files were in the shared directory.

Modifying the source files

First, modify edison.env. Based on which version of the Linux sources files you have, the location of the file is different. The quickest way to find it is by typing the following:

find * -name 'edison.env'

In my case, the file was originally located at:

edison-src/device-software/meta-edison-distro/recipes-bsp/u-boot/files/

As of February 2015, it is now located at:

edison-src/device-software/meta-edison/recipes-bsp/u-boot/files/

To change the root partition size, update rootfs in the partitions definition to the desired size in MB. In my case, I increased it from 512MB to 1024MB.

Next, modify edison-src/device-software/meta-edison-distro/recipes-core/images/edison-image.bb. Update IMAGE_ROOTFS_SIZE to the same size as rootfs in edison.env. Note that the unit is block size, so multiply whatever number you used in edison.env by 1024 and use the resulting value.

Building the image

Before going any further, I should mention that building an image can take HOURS. So, just keep that in mind before proceeding. To build the image:

  • Navigate to the edison-src directory.
  • Initialize the build environment: ./device-software/setup.sh.
  • Configure the shell environment: source poky/oe-init-build-env.
  • Build the image: bitbake edison-image.

Modifying flashall.sh

Once building the image is complete, copy the necessary files to the build/toFlash directory:

./edison-src/device-software/utils/flash/postBuild.sh

As of February 2015, no modification to flashall.sh needs to be made and you can skip the rest of this section. If you have an older version of the Edison source files, please continue reading.

To re-partition without using xFSTK (an Intel dependency that is a bit painful to install), modify edison-src/build/toFlash/flashall.sh.

To do so, change the script from:

echo "Flashing U-Boot Environment Backup"  
flash-command --alt u-boot-env1 -D "${VARIANT_FILE}"  

to:

echo "Flashing U-Boot Environment Backup and rebooting to apply partition changes"  
flash-command --alt u-boot-env1 -D "${VARIANT_FILE}" -R

dfu-wait

This modification causes Edison to reboot and resume flashing once it comes back online.

Flashing Edison with the new image

To flash Edison with the new image:

sudo ./edison-src/build/toFlash/flashall.sh

Follow the on-screen instructions. Note that the process can take some time (longer than 5 minutes), so please be patient. Once it’s complete, the console should look similar to this:

Using U-Boot target: edison-blank
Now waiting for dfu device 8087:0a99
Please plug and reboot the board
Flashing IFWI
##################################################] finished!
##################################################] finished!
Flashing U-Boot
##################################################] finished!
Flashing U-Boot Environment
##################################################] finished!
Flashing U-Boot Environment Backup and rebooting to apply partition changes
##################################################] finished!
Now waiting for dfu device 8087:0a99
Please plug and reboot the board
Flashing boot partition (kernel)
##################################################] finished!
Flashing rootfs, (it can take up to 5 minutes... Please be patient)
##################################################] finished!
Rebooting
U-boot & Kernel System Flash Success...
Your board needs to reboot twice to complete the flashing procedure, please do not unplug it for 2 minutes.

Checking the new image

Log into Edison and check if the partition has changed by typing df -h:

Filesystem                Size      Used Available Use% Mounted on
/dev/root               927.9M    306.5M    554.2M  36% /
devtmpfs                480.2M         0    480.2M   0% /dev
tmpfs                   480.5M         0    480.5M   0% /dev/shm
tmpfs                   480.5M    480.0K    480.0M   0% /run
tmpfs                   480.5M         0    480.5M   0% /sys/fs/cgroup
tmpfs                   480.5M    480.0K    480.0M   0% /etc/machine-id
systemd-1                 5.5M      5.1M    468.0K  92% /boot
tmpfs                   480.5M      4.0K    480.5M   0% /tmp
systemd-1                 1.8G      2.8M      1.7G   0% /home
tmpfs                   480.5M         0    480.5M   0% /var/volatile
/dev/mmcblk0p5         1003.0K     21.0K    911.0K   2% /factory
/dev/mmcblk0p10           1.8G      2.8M      1.7G   0% /home
/dev/mmcblk0p7            5.5M      5.1M    468.0K  92% /boot

Flashing succeeded! The size of /dev/root has increased!

comments powered by Disqus