Android recovery is a bootable partition, which lets you apply official system updates from SD Card, factory reset your phone or wipe its cache partition.
How to enter Sony Xperia LT29i Hayabusa recovery mode ?
Power off your device.
Boot in recovery mode by pressing and holding Volume Up and Power Button at the same time.
Release all buttons when the Sony Xperia LT29i Hayabusa screen flickers and in a few seconds the Recovery screen will appear.