JetPack can't update from 3.3 to 3.1 on TX2

I can update JetPack from 3.2.1 to 3.3 or 3.3 to 3.2.1 version without flash OS.
But I can’t update JetPack form 3.3 to 3.1 !

Is the reason because of the different L4T version?
Is there any other way to update different L4T version of JetPack without flash OS?
(We can’t update the OS because we have already change some settings on the kernel.)

best regards,
Lilian.lin

Yes, this is restricted by OS. Each JetPack version is tested and shipped with a specific version of OS and packages, like CUDA/cuDNN, with it. There is no guarantee on new version of packages with old OS.

*this is restricted by OS.
–> you mean the L4T, right?

*There is no guarantee on new version of packages with old OS.
–> so It can use old version of packages with new OS?

*Let me confirm again :
–>So we can update Jetpack without flash OS but they need use the same L4T, right?

Or It must be flash OS when installing the JetPack ?
If yes, why the JetPack has the option of “Flash OS image to Target” then we can select “no atcion”?