This applies to all major firmware updates... I have personally used a number of the ICS ROM's, LPS, LP7, LP8, LPD, LPF, LPG and LPI, LPY and LPZ and the new Jelly Bean firmwares, LS8, LSD, LSE, LSJ, MS1, LSN, LSS and LSW and they are all stable and work well. So it's no good blaming the firmware itself I'm afraid. Short version... FULL wipe and vanilla install 1. Press Factory Reset button and Format internal and external memories. 2. Check out your firmware for problems prior to re-installing your app's and settings. 3. Set your phone up from scratch by re-syncing to your Google account. Long version When you upgrade not only is the platform changed but all your app's and settings have to be reconfigured and integrated into the upgrade during the process. This is in an attempt by Samsung to retain everything on your phone so that you do not have to set it all up again after the change. If you stop and think about the millions of app's and the myriad of settings that this has to take into account then maybe you can understand why there are sometimes problems with SGSII phones after new firmware is installed. Some of these problems are caused by app's that are not suitable for the new firmware. Remember, not all app's on the Play Store may be compatible with your new firmware yet. Other app's, that work on your existing firmware, have to be updated for the new one, if possible, during the change over. No mean feat. (***Also, it should be noted, that the Jelly Bean file structure is changed from that used in Gingerbread and Ice Cream Sandwich and could affect app's that have been moved from phone memory to internal or external memory.) These problems can manifest themselves in all sorts of ways... from non compatible app's continually running and causing high battery usage and over heating not to mention eating up your storage with constant log or dump files. Settings that are giving Forced Closes or very long screen lags. High RAM usage or screen freezes and shut-downs can all occur because the user app's or data have not, or can not, be integrated successfully into the new framework automatically during the change over. Also, the downloaded firmware update itself may have been corrupted. This can easily happen with OTA, (Over The Air), updates where an interruption has occurred with the download. This has also been reported by some who have used the Samsung PC suite, Kies. However, unless you do a Factory Reset... you cannot be sure. See, ***, for how to re-install an update. So, what can you do? Well, I would strongly recommend a Factory Reset prior to upgrading. Settings > Back up and reset > Factory data reset Yes, I know, its a lot of hassle because you have your phone set up the way you like it on your existing firmware but it's a lot more hassle if things go wrong, as we can see from this forum. Besides, this is the very reason that Android include the Factory Reset feature. Besides, if you take your phone to a Samsung Service Point, this is usually the first thing they do. Having said that, I always do a Factory Reset and clean install so that there is no old setting or data from a previous ROM/firmware. OK, I'm rooted, so it is easier for me with various tools, etc; that are available to rooted users. However, you are only going to be doing it once or twice. The object of the Factory Reset is to return your phone's memory back to the out-of-the-box state with no user app's or data from your old firmware to cause problems. Make no mistake, if you are on, say, ICS, this does not revert you back to Gingerbread. You should take the time to check out your phone prior to re-installing your app's and settings to ensure that you are not experiencing any problems with the firmware itself. See, *** A Factory Reset will not touch your Internal* or External SD cards. However, I would strongly suggest copying any files from the Internal memory to your computer, using a USB cable and Windows Explorer, for safe keeping. * If you have any app's, settings or data stored on your Internal/External memory, you may also want to consider erasing this as well, after saving anything you wish to keep. Settings > Storage > Erase USB storage. The same applies to your external SD card if you have moved app's to it as when you move an app part of it stays in the phone memory and part is moved to your Internal/External storage. As you can see, this can cause problems in itself. You should also make sure that you are fully sync'd with your Google account so that Contacts and Calendar, etc; can be automatically restored after the Factory Reset and your subsequent sign in to your Google account. You can also, as a safeguard, save your Google Contacts by going into Contacts > Menu > Import/Export > Export to SD card and keep a copy on your computer. Providing your app's are all sync'd with the Play Store, they will start re-installing automatically, one-by-one after signing in with your Google account details, email/password. Your paid app's are still there as paid app's, so you do not lose them. The restore from the Play Store will take some time and should be done via Wi-Fi as there will be a lot of data downloaded. You may find that you have to, "set-up", some of your app's again or that there are updates for a number of app's or that you will need to manually re-download some again. This is no bad thing as it was probably these very things that were causing problems in the first place. If you have any passwords or Wi-Fi codes, etc; you should make a note of these before the Factory Reset. *** If, after a Factory Reset and prior to installing any app's, you find that your phone is still misbehaving this could be because of a corrupt installation of the firmware update originally. You can either take it to a Samsung Service Point or re-flash the firmware yourself using Odin and the instructions in #1.7, here. A useful app for backups, on un-rooted phones, is, "Helium", from the Play Store. However, be warned, you may well be restoring the very app's and settings that caused the problem to begin with. A safer method is to do a fresh install and set-up of each app. As I said, this may seem a lot of hassle but the alternatives are:- 1. Put up with your phone the way that it is. 2. Take it to a Samsung Service Point and get them to re-flash it for you... in which case you will lose everything anyway. 3. Re-install your old firmware using Odin, which may not solve the problem anyway, and possibly lose everything. The choice, as they say... is yours.