Many users have been searching for the stock ROM for the Galaxy Tab 2 10.1 as they want to return back to a fully working firmware or for warranty reasons (your warranty gets voided if you flash a custom ROM or root your Samsung Tab).
In case you are running a custom ROM, you must flash this stock firmware to make the UMS flash storage utility work on the Tab 10.1 (as that utility does not works on many custom firmwares).
Download the firmware from here. If you are coming from custom ROM, follow these instructions:
1. Boot in recovery (Power + Volume DOWN buttons at same time) and do a factory reset/wipe cache/wipe dalvik
2. Boot in download mode (Power + Volume UP buttons at same time)
3. Extract firmware on your computer and open odin
4. Connect your tablet
5. Put the firmware file in PDA in odin
6. Flash and reboot