Many power users install custom ROMs and overclocked kernels to get the most out of their tablets. The problem with tweaking your device is that you will not be able to download any official builds and updates from Samsung until you return back to stock software. This tutorial can also be helpful if you have installed custom software incorrectly and your device is not working properly.
This is for the Galaxy Tab 10.1 Wi-Fi (USA). Different countries use slightly different firmware so make sure that you only follow this tutorial if you have the USA variant. I am not sure what it will do to tablets from different countries.
Always back up everything first!
Step 1: Download the files here.
Step 2: Unzip the files and place them somewhere on your computer.
Step 3: Boot your tablet into download mode. First turn off your tablet. Then turn it back on while holding the volume down button until you see two Android logos. Press the volume down button until the right logo is selected. Press the volume up button to click it. Press the volume up button again to continue.
Step 4: Plug your Galaxy Tab 10.1 into your computer.
Step 5: Open Odin3_v1.85.exe. It is in a zipped archive called ODIN3_v1.85 inside of the folder where you extracted the zip you downloaded earlier.
Step 6: Press the PDA button in Odin and select P7510XABKMP_P7510UEKMP_HOME.tar.
Step 7: Press start and wait for it to finish.
Step 8: Once it has finished and rebooted, turn off your tablet and boot into recovery. This is similar to how you got into download mode, but this time select the left logo.
Step 9: Select wipe data/factory reset. Use the volume rocker to navigate and the power button to select.
Step 10: Select wipe cache partition.
You should now have stock firmware with no root access. This tutorial is an edited version of this post on XDA. Check there for more up to date files.