Doh and I just updated my new ps3 to 3.41 yesterday as I thought this wouldn't happen.
(Unless indeed you'll count as an issue impossibility to connect to PSN / Play online / Play 3D movies).
An upside to this would be that a jailbroken 3.15 system could show what has been removed from the firmware that enables otherOS so it's still possible for all us who have updated.
It's cool, I know that it would take more than just copying folders from one to another but I was just saying that it could be a very interesting find and that someday somrthing could come from compairing how different firmwares react. It might lead to more exploits being found on older firmware or maybe Geohot's original hack. I agree though it would be a very difficult task but it certainly will aid those who would try.