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Helper scripts

This page offers some documentation to extra scripts provided in the src/scripts directory


We create a lot of loopback devices in various scripts and there are conditions where we may leave around some loopback devices. This script provides a convenient way of unmounting any image directories in your chroot (for your board) and cleaning up errant loopback devices. Note, this script will not affect loopback devices / mounts in other chroots or outside the chroot.


gmergefs is an emerge wrapper that combines sshfs with emerge. It allows a developer to add a package to a live Chromium OS system using the developer's development system. The easiest way to use it is to pass a --remote flag that specifies the IP address of the remote device and pass the name of a package to install. You will also have to specify the board if you don't have a default one set up.

gmergefs requires that the host machine have ssh access to the root account of the remote machine and will prompt for this password when run (will need to edit sshd_config in /etc/ssh and sudo passwd to change root password). Test images by default have this enabled (see test section for password). Users of non-test builds will need to enable ssh access for the root account and set a root password.

gmergefs also requires you have fuse installed on your host machine (if you have fuse warnings when entering chroot, it will not work).

Note: By default gmergefs tries to install packages onto /usr/local of the remote system. If you are updating packages on the root fs you will need to pass --noonstatefuldev.

The following are some sample use cases:


gmergefs hangs: This is caused by sshfs hanging when mounting. Check that you can ssh as root from within your chroot i.e. ssh -o StrictHostKeyChecking=no root@your_ip. Also double check that you typed in the ip address correctly in the remote flag.

gmergefs has trouble writing to either or other file using --noonstatefuldev: gmergefs doesn't automatically remount your root dir to rw. Go onto your machine and run sudo mount -o remount,rw /

The output of the Chromium OS build process is a bootable binary gpt bin file that you can dd straight onto a usb key and install onto a device. However, often developers will want to make some modifications after the build process or make changes once an image is already on a usb key from the developer's development machine. This script makes it easy to do just that. This script will mount a bin or device specified in the --from parameter (e.g. /dev/sdc or ../build/images/.../.../chromiumos_image.bin) and mount the whole image under /tmp/m. Passing the same arguments in addition to -u (--unmount) will reverse the process. This can be used to emerge new packages onto an already created image as well as make small mod's or to just see what is in the image. See --help for more information.


Displays summary status for every git repository that is in a modified state. Helpful to easily see what changes you have across the entire source tree. This tool is found in depot_tools.