High Sierra - how to detect if OK to image OS vs. update

New Contributor II

So, it would appear that the official recommendation is to upgrade first, to allow firmware updates to execute, and then direct imaging of a machine is OK.

While we could just only allow imaging of machines that already have High Sierra installed, that doesn't account for machines that get clobbered. Additionally, in the spirit of avoiding unnecessary work (or rework), it would be great to be able to directly image when it will work.

From posts I've been seeing, it looks like it's only some models that need the update. I know I can query the mac to find its Identifier and/or its boot ROM version, but that won't help unless I know what IDs/versions need updating, what can be ignored, and what post updated ones look like.

Firstly, is what I'm thinking incorrect, and a wide range of machines do need firmware updates?

Secondly, anyone know of any convenient lists of identifiers / boot ROM versions to check against?