Downgrade ChromeOS on a Chromebook

[Jon Penn]

I work for a school and we are about to begin standardized testing. We operate a fleet of ~21000 Chromebooks. Several of those devices have not been on in a while and are running various versions of ChromeOS and the Chrome browser. The number of devices that are behind version 73 of chrome is much smaller, but it's still big enough that tracking them all down to update them "just in case" seems like a pain. Especially since many of them are only slightly behind. Is there a way I can take a Chromebook and install an arbitrary version of ChromeOS on it so I can run through a practice test and make sure there won't be any compatibility issues (I know 54 has compatibility issues)? The device needs to remain enrollable in Google Admin.

[Keith I Myers]

Good Morning,

You could re-image the Chromebook with whatever version you wish and pin the update via https://support.google.com/chrome/a/answer/3168106?hl=en

On Thu, Mar 28, 2019, 5:33 PM Jon Penn <907...@gmail.com> wrote:

I work for a school and we are about to begin standardized testing. We operate a fleet of ~21000 Chromebooks. Several of those devices have not been on in a while and are running various versions of ChromeOS and the Chrome browser. The number of devices that are behind version 73 of chrome is much smaller, but it's still big enough that tracking them all down to update them "just in case" seems like a pain. Especially since many of them are only slightly behind. Is there a way I can take a Chromebook and install an arbitrary version of ChromeOS on it so I can run through a practice test and make sure there won't be any compatibility issues (I know 54 has compatibility issues)? The device needs to remain enrollable in Google Admin.

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[DennisLfromGA]

To add, you can download the latest stable recovery version and even a few older ones if needed for your particular device(s) from here:

• https://cros-updates-serving.appspot.com

Just look for the codename and/or brand name and then download the version(s) you need from the 'Recovery' column.

Once the zip file is downloaded you can use the Chromebook Recovery Utility with the 'local image' option to write the media.

~Denny

P.S. Third try, sorry.

[Mike Frysinger]

to clarify posts here, while it might work to downgrade via older recovery images, we don't officially support downgrading via recovery to extremely old versions.

i think we're officially doing N-4 for enrolled devices (where N is current stable), but beyond that, it might be impossible and it'd be WAI.  we roll key versions specifically to prevent rolling back to vulnerable versions (e.g. to bypass FRE).

-mike

On Thu, Mar 28, 2019 at 2:33 PM Jon Penn <907...@gmail.com> wrote:

I work for a school and we are about to begin standardized testing. We operate a fleet of ~21000 Chromebooks. Several of those devices have not been on in a while and are running various versions of ChromeOS and the Chrome browser. The number of devices that are behind version 73 of chrome is much smaller, but it's still big enough that tracking them all down to update them "just in case" seems like a pain. Especially since many of them are only slightly behind. Is there a way I can take a Chromebook and install an arbitrary version of ChromeOS on it so I can run through a practice test and make sure there won't be any compatibility issues (I know 54 has compatibility issues)? The device needs to remain enrollable in Google Admin.

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[Jon Penn]

Thank you so much. This basically saved my week.