[Galaxy Tab 2 Q&A, Help & Troubleshooting] godsmack_dmx:
I updated my galaxy tab 2 7.0 p3100 to JB using this steps:

Pre-requisites

1. Install USB Drivers for Samsung Galaxy Tab 2 7.0 on the computer.

2. Enable USB Debugging Mode on the phone by navigating to Settings >> Developer Options.

3. Make a backup of all your important data before following the guide.

4. The Galaxy Tab 2 7.0 should be factory unlocked and not locked to any particular carrier.

5. Ensure the battery of the phone is charged more than 80 per cent.

6. The Android 4.2.2 XXDMG6 Jelly Bean firmware is compatible only with Samsung Galaxy Tab 2 7.0 P3100. Applying this to any incorrect variant might brick the device. Verify the model number of the Galaxy Tab 2 7.0 by navigating to Settings >> About Phone.

File Required

1. Android 4.2.2 XXDMG6 Jelly Bean Firmware (Mirror) for Galaxy Tab 2 7.0 P3100

2. Odin 3.07

Steps to Update Galaxy Tab 2 7.0 P3100 with Android 4.2.2 XXDMG6 Jelly Bean Firmware

Step 1: Extract Firmware zip file that you downloaded already from above link using winrar/7zip/winzip or any other extracting tool, you will get a .tar.md5 file and some other files.

Step 2: Extract Odin zip file and you will get Odin3 v3.07.exe along with few other files.

Step 3: Power off your phone.

Step 4: Boot the device into Download Mode by pressing and holding Volume Down and Power buttons together until a construction Android robot icon with a warning triangle appears on screen. Now press the Volume Up button to enter Download Mode.

Step 5: Run Odin on the computer as an Administrator.

Step 6: Connect the Galaxy Tab 2 7.0 to the computer using USB cable while it is in the Download Mode. Wait until Odin detects the device. When the device is connected successfully, the ID: COM box will turn blue with the COM port number. Additionally, the successful connected will be indicated by a message saying Added.

Note: If the Added message does not appear, then try re-install USB drivers or changing the port on the computer.

Step 7: Choose the following files in Odin from extracted P3100XXDMG6 firmware folder by using respective checkboxes:

Select the PDA checkbox, and choose the file named .tar or .md5.

Click the Phone checkbox, and choose the file with 'modem' in its name (ignore if there is no such file)

Click the CSC checkbox, and select the file with 'csc' in its name (ignore if such file is missing)

Choose the PIT checkbox, and choose the .pit file. Use only the file obtained during extracting in step 1 above, otherwise ignore it.

Step 8: In Odin, enable Auto Reboot and F. Reset Time checkboxes. Also, ensure the Re-Partition checkbox is chosen only if a .pit file was chosen in the previous step.

Step 9: Verify everything suggested in Step 7 and Step 8 is done correctly. Then hit the START button to begin the installation process.

Step 10: Once the installation process is completed, your phone will restart and soon you will see a PASS message with green background in the left-most box at the very top of the Odin. You can now unplug the USB cable to disconnect your device from computer.

The tab was very slow after rebooting with JB but after an hour it worked perfectly and fast. but in the next day it start to restart on it's own endlessly for about 2 hour than stopped restarting and work fine. But now every time I use the tab for no matter what I'm using it for it's begin the restarting loop for an hour at least.

The tab isn't rooted.

What I should do know to stop the restarting loop?