Use this method to hard reset your Samsung S5250 Wave525 Bada OS phone: Enter *2767*3855#. Warning! All your data including contacts, messages etc. will be lost! Copy all your necessary data/Contacts/Messages etc. to SIM or make backup to your PC before full reset! Take out SIM card before full reset.
Make sure phone is powered off , connect charger, hold power button, camera button and volume down button, it will go in charging mode. Then just turn it on.
If you know the hard reset using buttons / keys, pls leave a comment. All comments are welcome! :)