So I have a simple galaxy tab 3 tablet eunning an old version 4.1.2 I have tinkered with it a bit but cant find the resolution. Whenever I try to update my software it confronts me with this message "Your device has been modified Software updates arent available" I have no clue why but my device is marked as custom. How do I fix this and also I dont have a computer handy so thats not an option.