If you're having issues loading your Bloodborne save after applying firmware update 2.50 to your PS4, this should help you out.
Reddit user KBALLZZ encountered an issue after installing update 2.50 on his PlayStation 4. Bloodborne started reinstalling the day one patch again and when it was done he couldn't continue his game or load the previous save.
An error message would pop up saying 'update in progress' even though the update is already done installing. After trying to reinstall the game, signing out of PSN and back in etc.. to no avail, he fixed it by starting a new game and going back to the menu as soon as the level loads.
Once back in the main menu, the option to load his save game was now working.
The issue doesn't appear to be wide-spread, but there have been reports of other users needing to re-download their saves from the cloud to play the game after installing firmware update 2.50.