You can use Samsung KIES to update from computer since Samsung Galaxy Tab 2 allows you to do that.
Follow the below steps to update using Kies:
2. Now open Kies application from your PC.
3. Connect your device to your PC or laptop using the USB cable.
4. Once Kies recognizes the device, a popup window will appear.
5. Click Update.
6. Read the Allow saving of information statement and select Allow saving or Proceed without saving and then click Start upgrade.
7. Kies will begin downloading firmware upgrade components from Samsung servers.
8. During the upgrade process, you will see the Android logo on your devices screen and Kies will show progress bar.
9. Click OK after update completion.
You can now disconnect your device from the PC. Once the device has rebooted it will be ready to use.