Virtuous Flame has released Open CMA v5 which is a patch that prevents the PS Vita Content Manager Assistant from connecting to the internet. This patch will bypass the pre-intalled function of the Vita that forces you to update when you are connected to the internet. See below for the installation instructions.
"- extract the archive in your CMA folder (program files/Sony/Content Manager Assistant by default)
- quit the CMA if it is running on your PC
- execute "run.bat" (you need to run it in "Admin mode" on windows 7
- That's it, now the CMA should run without requiring to be connected to the internet"
Source