A few days ago we discovered that it is compulsory to be connected to the internet in order to use the Content Manager Assistant. Although I found out later that this tool is not necessary for media files, it is still compulsory to use it if you want to copy games and savedata from and to your PS Vita. Having to be connected to the internet while you copy files between two pieces of hardware you own is inconvenient, unsafe, and technically not necessary. It is therefore an unnecessary “feature” of the Content Manager Assistant that was put here by Sony for no other good reason than force people to update their console to the latest firmware on a regular basis.
Famous PSP Dev Virtuous Flame released today a tool called OpenCMA, which is basically a patch to the Content Manager Assistant (on the PC side) that will prevent it to connect to the internet.
I tested it myself, and it works fine, although Virtuous Flame told me it might still be unstable. It is not yet guaranteed that this tool will be enough to prevent the console from upgrading its firmware without your consent, but hopefully this should help.
As a reminder, if you want to keep using the CMA normally, a firmware upgrade is compulsory every time Sony says so. Since every firmware upgrade comes with a new license and a new Terms and Conditions contract, it means that Sony can progressively change the contract you agreed with when you initially bought your vita, and entirely lock you out of some core features (such as backing up the games you bought and your save data to your PC) if you refuse the new contract. The OtherOS lawsuit in the US has also shown that Sony can remove any feature they want from the system you bought, and not be afraid of any legal consequences. This patch is also useful for these kind of unfair situations.
download and installation explanations here
Source Virtuous Flame, thanks J.F. for the tip!