PS3 Hangs on Load

Since the last PS3 upgrade (about 1 week ago), only 30% of our previous worlds will load. Most of the time, the console hangs on load and we have to hard reset. We've been playing the PS3 version of Minecraft as a family. We have tried loading 10+ different saves on 5 different consoles. We've even tried restoring a previously backed-up save from USB. Only 3 of these actually loaded, and were glitchy until after the first save. Hope you can help.