On installs where no OTA upgrade is possible, system-image should not attempt an upgrade

[Oliver Grawert]

On readwrite images or installs done using the cdimage zips OTA upgrades are obviously not possible.
nontheless going to System-Settings -> Updates, starts the updater which will spin endlessly ... or even worse actually updates the rw loop mounted image, the app should have some check if an image is rw and simply refuse to update (probably telling the user in a friendly manner about this)

[Barry Warsaw (barry)]

I'm not completely convinced that r/w images should be completely prevented from doing image based updates. For example, I switch over to r/w for testing, but I still want to update via s-i. Perhaps we can look for /userdata/.writable_image and refuse to update *unless* there was some other magical file present, e.g. /userdata/.allow_image_updates

When doing cdimage installs, does /userdata/.writable_image exist? If not, what the best way to differentiate between the two installs?

[Sebastien Bacher (seb128)]

Thanks, we don't have a design currently for that and the service doesn't tell us that afaik, if we get those we could adapt the ui to deal better with the case.

Note that the settings are going to mix system and click updates soon, are those images not able to install/update clicks either?