It will remove all the data ,contacts and apps that you installed
how to remove username password karbonn A21 solution is available on net but there is no home key button on handset
Press Power key + Volume up key + Home Key
and then select clear data.
karbonn A21 Restore Factory Hard Reset Format Phone.So lets start the karbonn A21 Restore Factory, karbonn A21 Hard Reset.Turn Off the mobile phone for few mints.karbonn A21 Remove Pattern Lock.
Restore Hard reset will set your phone in origional factorry settings. It will remove all the data and apps that you installed. Your contacts will be removed and you have to add them again.