[Galaxy S II Q&A, Help & Troubleshooting] gyaku_zuki:
Boy I'm not having great luck with my hardware atm. My Nexus 7 has got some serious lag issue, probably needing a factory restore, and now my SGS2 is playing up and looking like it might need the same. I'd appreciate the help before I go to that - not sure where I am on backups, I think this problem has been lingering for a while unnoticed, and its possible my scheduled Titanium task hasn't worked in a while because of this.

So let me run through. I was trying to update a few apps in the app store, and I got 'the package file is invalid' errors over and over. I was a little confused, and suddenly I was getting a flickering alert for 'low on application space' that would come and go.

I went into applications to see what my space was and it was fine, 400mb free. But I noticed that all of the apps were reading as zero size. I tried removing one I knew was big, and the free space adjusted by a real amount, but no change to the sizes in the listing. I went thru and uninstalled a bunch just to be sure. Even after this, I could still not install any apps without getting the invalid message.

I decided to restart and wipe the cache, thinking maybe something had gone wrong there. No change. All the installed apps were working ok, though, no problems running things. So, I decide that something minor has corrupted, and that a reflash of the current firmware would maybe do the job (which is a stock XEU build of ICS). I have 'Mobile Odin' and keep the current firmware file on the SD just in case. I of course want to run a backup first, so I fire up Titanium, which fails to do the backup, with an error about something catching fire trying to 'do calculation'. I begin to figure that something worse has happened by this point.

I decide to go ahead with the reflash using Mobile Odin. It seems to load fine, I tell it to wipe the cache and so on. The flash goes fine, and the phone reboots. I expected it to go through the little optimising applications thing it does, and true enough I see this box load up, saying 'start applications' and the spinning wheel. Then, it abruptly closes, and I get my home panel...

But here's where it goes severely wrong - every app I can think of now crashes, displaying the 'unfortunately XXX has stopped'. Boxes and boxes, for basically every app that in any way runs at startup, every widget, even my Swift Key and Swipe keyboards. Yikes! After clearing the huge backlog of boxes, I start trying to open stuff, and it quickly becomes apparent that no app will work, save for those that are physically part of the firmware (such as Settings, Messages, Phone, Contacts, Memo, Camera). Basically, unless its a stock app, it's just dead. My SD apps show up as if they aren't found, with the little grey SD box. I can't even open the Play Store to try redownloading an app.

I'm going to try, once I'm home from work, reflashing the firmware using desktop Odin. But, failing that, I will need a factory restore it would seem. Basically, I'm looking help either fixing the problem without a factory restore, or a way to back up my data (messages and app data) in case my Titanium Backups are old or broken.

Thanks :/

Edit: When I do a *#1234#, my CSC comes up as 'Unknown'. Would this cause these issues?