If you have nokia c2-06 and its firmware corrupted or out dated you can fix this problem by its flash files. Flash files are used for do software or update mobile old firmware. Some times your mobile working so slow or completely break at this stage you will need to complete flash by using UFS micro box or other flashing tool. Before flashing you will need to download its latest flash files after that just connect your mobile with computer through usb data cable. Flash file consist on three main files like mcu,ppm and cnt.
Before flash please don't forget to take backup of your important data like images,messages and contacts because after completing of flashing you will lose your all of data and your mobile will restored in its original settings.