This guide will teach you "how to use FASTBOOT commands in case your Device got Soft-Bricked with NO DISPLAY"!!..
Here we begin.
Let's describe Softbrik: Anything caused to your phone except damage to Hardware of your phone which put your Device into a state where it is not booting up and kept showing White, Gray, Blue or Black Screen or Either It gets stuck at Company logo Screen. This may occur if something goes wrong during Rooting, flashing Recovery or ROMs or during Updating in Recovery Mode or either being caught by some wrong software or VIRUS !!!
Preface to the Guide:
Fastboot is a command line tool used to directly flash the filesystem in Android devices from a host computer via USB. It allows flashing of unsigned partition images and also can erase partitions. Its a part of Android Developement Kit (Android SDK).
Use of FASTBOOT is disabled in production devices since USB support has been disabled in the bootloader. You must have an Engineering SPL, or an SPL that is S-OFF or Unlocked bootloader to use 'fastboot'.
After installing the Android SDK or ADB Standalone you can use 'fastboot' in addition to the more common ADB . One can use the attached .android folder if u want to skip downloading Android SDK.
Verify SPL S-OFF or Bootloader Unlocked:
Not required for Karbonn or Micromax !! But certain Production Devices like Sony HTC LG etc may need bootloader to be unlocked before carrying out this process. My simple advice to people is.. "If you enjoy experiments on your device, you must be ROOTED and to ROOT you device you may need to have unlock bootloader"
Preparations:
(1) Download attached .android.zip, Extract and place .android folder on C:/ drive of your PC. So the path of this folder will look like C:/.android
(Never remove this ".android" folder from C:/ coz you will require it whenever u want to experiment with you Droid using ADB or FASTBOOT methods. I assure... You can do a lot more with it; if you really explore how to use various commands !!!)
.android folder is containing adb.exe , fastboot.exe and related drivers adb_usb.ini , android_winusb.ini AdbWinApi.dll and AdbWinUsbApi.dll and other files; all together not more than 800KB
(2) Connect Device in 'USB debugging ON' mode. Ensure Drivers for your Device are already installed on the host computer . Note: I recommend you should always keep USB Debugging opetion ' ON ' as it only can help you, in case, your device get SoftBricked and you cant see anything on Device Screen. Remember that with USB debugging 'OFF ' your Device can't communicate with your Host Computer. Note: I recommend you should always keep USB Debugging opetion ' ON ' as it only can help you, in case, your device get SoftBricked and you cant see anything on Device Screen. Remember that with USB debugging 'OFF ' your Device can't communicate with your Host Computer.
(3) Host Computer Ability to Launch Command Prompt: On Windows-XP or earlier, to start ADB (Android Debug Bridge) You need to locate your folder containing adb.exe where as Windows-7/Vista/ Other-Latest-OS can directly launch command prompt from the Folder itself by Shift+Right Click on Mouse and Selecting " Open Command Prompt from here". Hence 'Locating 'adb' folder-steps' are for XP users only, However higher OS users can skip it and can directly start giving 'adb' commands after opening cmd from .android folder.
(4) So now, Open Command Prompt (in Windows XP), it will return like this:
Microsoft Windows XP [Version 5.1.2600] (C) Copyright 1985-2001 Microsoft Corp. C:\Documents and Settings\USERNAME> (As our adb.exe is in C:/.android.... we will type: Cd C:\.android) C:\Documents and Settings\USERNAME>Cd C: \.android (Hit Enter) C:\.android>
Let's give command to detect attached device by writing: ' adb device'. On hitting enter it will list all devices attached to your PC.
C:\.android>adb devices
List of devices attached
XXXXXXXX-XXXX device
Now u can do a lot while your Device is attached in 'adb mode ' e.g.:
1. Rebooting into Bootloader (FASTBOOT)
2. Installing apps on as /system/app or / data/app
3. Copying Files to/from your SDCARD
4. Pulling Files or Apps already installed on your /system or /data partition
To Understand adb commands and how they work please read: http://developer.android.com/ tools/help/adb.html#commandsummary
Let's come back to ISSUE: "We have a SOFTBRICKED devices !!!"
(1) Booting into FASTBOOT mode: Let's come back to ' fastboot' as we need to flash new ROM or to apply update.zip in a Softbricked device.Note: Let your device remain connected to PC and don't disconnect untill You finish you job-successfully and get your Device again in working Factory Condition.
"fastboot reboot-bootloader" This command is used to reboot your device into bootloader i.e into fastboot mode ) and In this Mode your device will stuck into boot logo only and u cant operate it. Well we are not concerned as we already have a bricked device with no screen display !!!. Lets go ahead...on cmd follow:
C:\.android>adb reboot-bootloader
C:\.android>fastboot devices
XXXXXXXXXXXX fastboot
(this confirms yr devices is in fastboot mode now.)
(2) Unlocking-ReLocking Bootloader:
(Skip if u working with pre-unlocked devices)
C:\.android>fastboot oem unlock
...
SUCCESSFUL
finished. total time: 118.063s
(Accept/Decline warning on your devices screen. Select YES to Unlock ) (Once ROM is flashed) To relock Bootloader use command: fastboot oem lock:
C:\.android>fastboot oem unlock
...
SUCCESSFUL
finished. total time: 118.063s
(Accept/Decline warning on your devices screen. Select YES to ReLock) (Skip if u working with pre-unlocked devices)
(3)Get 'Recovery.img' and 'Update.zip' for your Device:
Lets Wipe the Data and then proceed to Flash new ROM/Update.zip
IMPORTANT: Copy the stock recovery.img and your devices' Update.zip [ in .android folder(You can get it even by searching it in this forum or by Googling for it..) So I assume that you have it....in your .android
Abbreviations:
recovery.img = Stock Recovery of your Device
Update.zip = Update Package/Stock ROM of your Device
Let's start wiping and updating process with following commands:
(4)Wiping Old Data and Flashing new Update.zip:
C:\.android>fastboot -w
SUCCESSFUL
C:\.android>fastboot update Update.zip
(Here Replace Update with Full Name of your any Update.zip that you copied to .android folder)
Your phone will update and automatically reboot into the Factory State. Cheers!!!
Note: Its important to spell the file name correctly that u want to flash/update. No space between name are allowed. This process will only be successful if your device is still carrying recovery partition 'intact'.
Explaining Last Step:
We used simple logic in last procedure/ Its nothing but updating using Recovery Mode.
1. Reboot device
2. Apply Update.Zip from SDCARD
3. Wipe userdata on device/Factory Update
4. Wipe Cache on Device
As the default curser in recovery UI remains on Option-1 and we needed to choose Option-2. Hence to select " Apply update for sdcard " we pressed 'Vol(-)' ONCE and then to Confirm and execute that option Tapped 'POWER' button TWICE .
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