In an effort to help the team working on the JFW DH release, they have in advance over at Demonhades released a tool to check the lowest version of firmware your PS3 Console can downgrade to in an effort to build a list of factory min. values and their matching models!
Tutorial created by DeathHades.
This tutorial will teach you to how to know the base firmware of your PS3 with a few steps and images.
1 - Copy the MinVerChk to your USB stick, the same way as if it was an firmware upgrade.
2 - Insert the USB stick into the PS3.
3 - Start a firmware update like normal from XMB (Don't worry, it will not update!)
4 - It will shortly fail and display the Firmware Base Value
Below is the screenshots from running the above steps.
Not sure how we can submit the info to them, I think you need to be a member of their forums, but for now at least we can run it on on our own PS3 models, and post a list of machines that our valued crunching members have, not sure if this means they are looking for a way to BYPASS this factory set limit by building up a database of "min. values", but new tools are always handy to have! -- Many thanks!