After over 3 months of development and experimentation, I’m now glad to announce that the system images are now the recommended way to deploy and update the 4 supported Ubuntu Touch devices, maguro (Galaxy Nexus), mako (Nexus 4), grouper (Nexus 7) and manta (Nexus 10).

Anyone using one of those devices can choose to switch to the new images using: phablet-flash ubuntu-system

Once that’s done, further updates will be pushed over the air and can be applied through the Updates panel in the System Settings.

You should be getting a new update every few days, whenever an image is deemed of sufficient quality for public consumption. Note that the downloader UI doesn’t yet show progress, so if it doesn’t do anything, it doesn’t mean it’s not working.

Those new images are read-only except for a few selected files and for the user profile and data, this is a base requirement for the delta updates to work properly.

However if the work you’re doing requires installation of extra non-click packages, such as developing on your device using the SDK, you have two options:

Stick to the current flipped images which we’ll continue to generate for the foreseeable future. Use the experimental writable flag by doing touch /userdata/.writable_image and rebooting your device.

This will make / writable again, however beware that applying image updates on such a system will lead to unknown results, so if you do choose to use this flag, you’ll have to manually update your device using apt-get (and possibly have to unmount/remount some of the bind-mounted files depending on which package needs to be updated).

From now on, the QA testing effort will focus on those new images rather than the standard flipped ones. I’d also highly recommend to all our application developers to at least test their apps with those images and report any bug that they see in #ubuntu-touch (irc.freenode.net).