Flashing a new ROM completely wipes the internal storage. Back up all important photos, documents, and contacts to an external microSD card or a computer.
Following these steps will provide the best possible Android 7.1.2 experience on your Galaxy Tab 2 10.1 , breathing new life into your device.
Go to Settings > About Tablet and tap "Build Number" 7 times to enable Developer Options, then turn on USB Debugging. Flash TWRP Recovery: Boot tablet into Download Mode (Power + Volume Down).
Check the following partitions: , System , Cache , and Data .