I created a nandroid backup of the stock firmware, however I quickly deleted it during a wipe when flashing my first custom ROM, which was GraveD's v3.0. It seemed to go OK, but then it would start to freeze up and reboot on it's own. This seemed to happen mostly under load, and especially when trying to install apps from the Play store. I tried going back to the stock kernel, thinking that could be the problem. It stopped the crashing, but then wifi wouldn't work. So I could choose between having a tablet that crashes all the time, and has difficulty installing apps, or one without wifi. Both were basically useless.
I tried installing another custom ROM, GigaWatts Pro. Again, flashing seemed to go well, and the ROM also seemed to work very nicely for a couple of days. No random reboots, and wifi worked great. I spent a few days downloading all of my apps and getting things set up the way I like, when yesterday something went wrong. Perhaps the tablet lost its root (is that possible?). All of a sudden, apps are crashing all over the place (Unfortunately, [insert app name] has stopped). Titanium backup hangs at "Asking for root...". Installing apps is also difficult again. The tab doesn't reboot on it's own, but Play Services crashes constantly. Whenever I try to get into developer options, the Settings app crashes. I'm not even 100% sure USB debugging is enabled right now, although I'm still able to flash using ODIN.
I tried doing a factory reset and re-installing GigaWatts. Same problems. Tried making sure the root was OK. Same problems. I've tried using twrp 184.108.40.206 as well as 220.127.116.11 with no luck.
Right now, I've downloaded the stock firmware for Canada T520UEUANI1 4.4.2 (although the tab was bought from a USA site). I assume this also installs it's own Kernel. It shows Kernel version:
Mon Sep 15 17:44:40 KST 2014
I'm experiencing the same problems. Google Play Newsstand crashes every 10 minutes or so. Settings is almost useless. Installing apps is problematic.
Can anybody tell me if there's something I'm missing? Anything left to try? Does it sound like a hardware/ROM/kernel problem? If it's hardware, can I still utilize the Samsung warranty after trying to flash custom ROMs? I'm going to try to download another Cellular South stock ROM, but it seems like the problems are persisting regardless of which ROM i have installed, so I think it's something else (kernel or hardware-related).
Any help is GREATLY appreciated. My new tablet is basically useless, and I've run out of ideas.