This is the first ever guide written by me, and I am not an expert in android and recovery, so please pardon if any mistakes are found. Lets correct if any.
First of all this is in preliminary stage and hence you will have to search and download required softwares on your own. I am trying to update this post with all the required links but it will take some time, (and I don't have much). The only reason I posted this is to save any karbonn a21 users time if his device gets bricked. I had to keep my business aside for a whole day to recover my Karbonn A21 in working state.
You will have to keep handy :
1) CWM by Eklovya
2) AIO Flasher by Fonehacker
3) Different ROMs (*.zip) and A9+ system image (system.img)
Also use Root_with_Restore_by_Bin4ry_v18 to root your karbonn a21 whenever necessary.
First of all you must understand that three partitions are necessary in Android : 1) Boot, 2) System, 3) Recovery
Other than these, there are Data, Cache, etc.
Unbricking any handset involves
1) Repairing Boot partition in fastboot mode using AIO Flasher to flash a proper boot.img file to the handset.
2) Installing proper Recovery partition in fastboot or normal mode using AIO Flasher, CWM Recovery by eklovya is a suitable solution.
3) Installing the System partition from a proper system.img file using AIO Flasher, or from a .zip file (Custom ROM) or a backed up ROM through CWM recovery.
Fastboot mode :
Fastboot mode is a handset mode where it is possible to flash different partitions through a simple USB cable and PC. It can be activated on Karbonn A21 by keep pressed [Volume Up] key during power on (read : before power on) until your screen glows in green colour. Instantly release [Volume Up] key or your A21 may boot into recovery partition. On your PC proper drivers must be installed and fastboot.exe from Google is required to flash the partitions to the handset. AIO Flasher is a good GUI solution for that.
Recovery :
During the above process, if you keep the [Volume Up] key pressed until the screen glows red, and then release the key, you enter into recovery mode.
First of all this is in preliminary stage and hence you will have to search and download required softwares on your own. I am trying to update this post with all the required links but it will take some time, (and I don't have much). The only reason I posted this is to save any karbonn a21 users time if his device gets bricked. I had to keep my business aside for a whole day to recover my Karbonn A21 in working state.
You will have to keep handy :
1) CWM by Eklovya
2) AIO Flasher by Fonehacker
3) Different ROMs (*.zip) and A9+ system image (system.img)
Also use Root_with_Restore_by_Bin4ry_v18 to root your karbonn a21 whenever necessary.
First of all you must understand that three partitions are necessary in Android : 1) Boot, 2) System, 3) Recovery
Other than these, there are Data, Cache, etc.
Unbricking any handset involves
1) Repairing Boot partition in fastboot mode using AIO Flasher to flash a proper boot.img file to the handset.
2) Installing proper Recovery partition in fastboot or normal mode using AIO Flasher, CWM Recovery by eklovya is a suitable solution.
3) Installing the System partition from a proper system.img file using AIO Flasher, or from a .zip file (Custom ROM) or a backed up ROM through CWM recovery.
Fastboot mode :
Fastboot mode is a handset mode where it is possible to flash different partitions through a simple USB cable and PC. It can be activated on Karbonn A21 by keep pressed [Volume Up] key during power on (read : before power on) until your screen glows in green colour. Instantly release [Volume Up] key or your A21 may boot into recovery partition. On your PC proper drivers must be installed and fastboot.exe from Google is required to flash the partitions to the handset. AIO Flasher is a good GUI solution for that.
Recovery :
During the above process, if you keep the [Volume Up] key pressed until the screen glows red, and then release the key, you enter into recovery mode.