ADB AND FASTBOOT COMMANDS DETAILED EXPLANATION

ADB
    ADB mode of an android phone means that the usb debugging enabled mode. 

FASTBOOT
     Fastboot is a protocol that can be used to re-flash partitions on your device (update the flash file system in Android devices).


COMMON COMMANDS
On PC run Command Prompt as Administrator.

• To check connected devices when ROM is running on phone:
  Code:

  adb devices

• To boot into bootloader mode:
  Code:

  adb reboot bootloader

• To check connected devices when in bootloader mode:
  Code:

  fastboot devices

• To boot into ROM:
  Code:

  fastboot reboot

• To boot into recovery:
  Code:

  fastboot reboot recovery

There are some common Linux commands which can be used in combination with these commands to perform certain operation. However, ADB | FASTBOOT is not necessarily required for these Linux commands. These can be run directly from Terminal Emulator in ROM or Custom Recovery. Some of them are given below.

UNLOCK BOOTLOADER
NOTE: Some newer devices don't allow unlocking of bootloader directly to ensure more security. Instead an official method is provided to unlock BL using PC.
Read here to know about the risks of BL unlocking.

To check the bootloader status:

Code:

fastboot oem device-info

“True” on unlocked status.
If "false", run the following to unlock:

Code:

fastboot oem unlock

FORMAT DATA PARTITION
This will erase your data.

Code:

fastboot format:ext4 userdata

It can be performed on other flash partitions as well. A general syntax is 'fastboot format:FS PARTITION'

FLASH RECOVERY
Download recovery.img (specific for your device) to adb folder.
To test the recovery without permanently flashing, run the following:

Code:

fastboot boot recovery.img

On next reboot, recovery will be overwritten by previous recovery.
Or to permanently flash recovery, run:

Code:

fastboot flash recovery recovery.img
fastboot reboot recovery

Stock ROM's often tend to replace custom recovery with stock one on first reboot. That's why, booting into recovery is recommended before booting into ROM.

FLASH KERNEL
Download boot.img (specific for your device) to adb folder and run following:

Code:

fastboot flash boot boot.img

FLASH ROM
Download ROM.zip (for your device) created for fastboot i.e. with android-info.txt and android-product.txt.
To wipe your device and then to flash .zip:

Code:

fastboot -w
fastboot update </path/to/your/Rom.zip>

GAIN ROOT (Not recommended method. Better flash directly through custom recovery).
Root is required to modify the contents of /system. You can read here further.
Download (flashable) supersu.zip and custom or modified recovery.img (having support to flash .zip files) to adb folder and run the following:

Code:

fastboot boot recovery.img

Now once you are in recovery, adb will work instead of fastboot.
To copy files from PC to device and then to extract files, run the following:

Code:

adb push supersu.zip /tmp
adb shell /sbin/recovery --update_package=/tmp/supersu.zip

BACKUP / RESTORE APPS & DATA (From/To PC)
To backup and restore all apps and their data:

Code:

adb backup -apk -shared -all -system -f C:\backup.ab
adb restore C:\backup.ab

Read here for details.

COPY WHOLE PARTITION IMAGE (within device)
This method can be used to backup whole device e.g. to backup /data/ including /data/media/ i.e. Internal SD Card which isn't backed up by custom recovery (TWRP). Or you can get any partition image for development purpose. This method retains complete directory structure as well as file permissions, attributes and contexts.

• To jump from windows command prompt to android device shell:
  Code:

  adb shell

  These commands can also be given from Recovery Terminal instead of ADB.
• To get SuperUser access (in ROM):
  Code:

  su

• To list all available partitions or mount points on device:
  Code:

  cat /proc/partitions

  Or go to "/dev/block/platform/" folder on device. Search for the folder having folder "by-name" inside it. It's msm_sdcc.1 (on Nokia X2). Run the following:
  Code:

  ls -al /dev/block/platform/*/by-name

  Or simply use DiskInfo app to get partition name you want to copy. Say you want to copy /data (userdata) partition. On Nokia X2DS, it is mmcblk0p25.
  To confirm:
  
  Code:

  readlink /dev/block/bootdevice/by-name/userdata

• Run the following to copy partition:
  Code:

  dd if=/dev/block/mmcblk0p25 of=/sdcard/data.img

  or
  Code:

  cat /dev/block/mmcblk0p25 > /sdcard/data.img

  or
  Code:

  dd if=/dev/block/bootdevice/by-name/userdata of=/sdcard/data.img

  data.img will be copied to your SD card.
  It also works inversely (restore):
  
  Code:

  dd if=/sdcard/data.img of=/dev/block/mmcblk0p25

  data.img from your SD card will be written to device.
  Similarly you can copy system.img, boot.img or any other partition. However boot.img and other partitions may not be copied in ROM but in recovery mode only. So better use recovery for dd except if you're​ going to dd recovery partition itself. You can read here more about android partitions.

COPY WHOLE FOLDER (within device)
This method can be used to backup folders like /data/media/ which isn't backed up by custom recovery (TWRP).

To jump from windows command prompt to android device shell:

Code:

adb shell

These commands can also be given from Recovery Terminal.
To get SuperUser access (in ROM):

Code:

su

To copy from Internal Memory to SD Card:

Code:

cp -a /data/media/0/. /external_sd/internal_backup/

Or if you don't have SU permission:

Code:

cp -a /external_sd/. /sdcard/

To copy from SD Card to Internal Memory:

Code:

cp -a /external_sd/internal_backup/. /data/media/0/

However, if you are copying to an SD card with FAT32 file system, android permissions of files won't be retained and you would have to fix permissions yourself. In this case, you can use tar command to create archive of files along with their attributes ( permissions: mode & ownership + time-stamps) and security contexts etc. But FAT32 FS has also a limitations of 4GB maximum file size. You may use "split" command along with "tar" to split the archive in smaller blocks. Or use exFat or Ext4 filesystem for larger file support. Ext4 would give higher writing speed in Android but not supported in Windows i.e. SD card can't be mounted in Windows. MTP however works.
To jump from windows command prompt to android device shell:

Code:

adb shell

To get SuperUser access (in ROM):

Code:

su

To copy from Internal Memory to SD Card:

Code:

tar cvpf /external_sd/internal_backup/media.tar /data/media/0/

To extract from SD Card to Internal Memory (along with path):

Code:

tar -xvf /external_sd/internal_backup/media.tar

To extract from SD Card to some other location, use "-C":

Code:

tar -xvf /external_sd/internal_backup/media.tar -C /data/media/0/extracted_archive/

COPY WHOLE FOLDER (From/To PC)
This method can be used to backup folders like /data/media/ which isn't backed up by custom recovery (TWRP).

To copy from PC to device:

Code:

adb push \path\to\folder\on\PC\ /path/to/folder/on/device/

To copy from device to PC:

Code:

adb pull /path/to/folder/on/device/ \path\to\folder\on\PC\

After copying from PC to device's Internal Memory (/data/media/), you might get Permission Denied error e.g. apps can't write or even read from Internal Memory. It's because Android (Linux) and Windows have different file permissions system. To FIX PERMISSIONS, boot into recovery and run following commands:

Code:

adb shell

To take ownership of whole "media" directory:

Code:

chown -R media_rw:media_rw /data/media/

To fix permissions of directories:

Code:

find /data/media/ -type d -exec chmod 775 '{}' ';'

To fix permissions of files:

Code:

find /data/media/ -type f -exec chmod 664 '{}' ';'

PASSING FASTBOOT ARGUMENTS
Fastboot supports passing options. For example, while booting a modified kernel image with FramBuffer Console support, console device and its font can be provided as option:

Code:

fastboot boot -c "console=tty0,115200 fbcon=font:VGA8x8" boot-fbcon.img

 




SOURCE : XDA DEVELOPERS FORUM