I get what you are saying.
I thinks it updates and takes away the things the real updates put it.
Why can't we make our own keys?
We can't make out own keys because the ps3 won't recognize it. It needs to use the decryption keys it already has, to decrypt the next firmware.
---------- Post added at 04:40 PM ---------- Previous post was at 04:38 PM ----------
I'll use an example, 3.56 made, 3.60 was made after 3.56. 3.60 was encrypted using 3.56 encryption keys so It could be decrypted using 3.56 decryption keys. If we used random keys for 3.60 then 3.56 wouldn't be able to decrypt it since the keys don't match.