newbie question: iOS install up<>down

sfphoto

macrumors 6502
Original poster
Jun 10, 2010
283
5
I have some older iDevices that can be upgraded to iOS 8 or 9, but no further due to age.

So... if I upgrade an old iPad2 to iOS9 which Apple is still signing, can I then find (in my Mac) the SHSH Blobs?
I would use iTunes and a Mac to upgrade assuming that is the way to do it if one wants to have the SHSH Blobs.

If so can I then use those Blobs with the proper IPSW file for a newer iPad that has 12 and downgrade it to 9? (The newer iPad came with iOS8).

If what I have outlined is coherent and do-able is there something in layman's terms describing the process that you can point me to?