Unlock BootLoader

BootLoader, is just like initial Bootup we do in our desktops, and laptops, for those who have installed a Win 98 OS , will know the value of Boot Floppy Disk.

To install Custom Rom, we need make changes to Motorola's default Boot Loader which loads its own Stock Rom. This will override MotoBlur Login and you can access your phone without even needing a SIM card.

For unlocking bootloader, the best link is cyanogenmod's wiki. These are easy steps follow one by one and it definitely works.

Link Below:
http://wiki.cyanogenmod.com/wiki/Motorola_Atrix_4G:_Full_Update_Guide#Unlocking_the_Bootloader_with_RSD_Lite_.28Windows.29

Unlocking the Bootloader

If the bootloader of the Motorola Atrix 4G has already been unlocked, you may skip this section.

WARNING: UNLOCKING THE MOTOROLA ATRIX 4G'S BOOTLOADER WILL VOID THE WARRANTY.

Unlocking the Bootloader with RSD Lite (Windows)

1. You will need fastboot on the computer to unlock the bootloader of the Motorola Atrix 4G. Follow the Android SDK guide, to get fastboot on the computer.
2. Download RSD Lite, the Motorola Drivers, and appropriate unlockable bootloader:
   • RSD Lite 5.7: Download

     md5: feb9a71470ee539e074bf420a2e4d8bd

   • Motorola 5.5.0 device drivers: Download
   • AT&T Atrix 4G Only: Unlockable Bootloader: Download

     md5: a5da47565160e0f95b84a1e769b9028b

   • International Variants Only: Unlockable Bootloader: Download

     md5: f609dbc4c5842f9654e44a1980375100

3. Unzip the correct bootloader and place it somewhere easy to access.
4. Install RSD Lite.
5. Once RSD Lite is installed, install the Motorola device drivers.
6. Power off the Motorola Atrix 4G.
7. Boot into RSD Protocol mode by holding down the Volume Up button while the device powers up.
8. Connect the Motorola Atrix 4G to the computer via USB.
9. Open RSD Lite.
10. Click on the "..." button next to the filename box and select the unlocked bootloader .sbf file.
11. Once it is selected, hit Start and wait for it to finish flashing the device.
12. It should take a few minutes to flash the unlockable bootloader, and the device may reboot multiple times. Once RSD lite reports that it's finished (or appears to be waiting for the device even though the device is booting into android), the device should be powered off.
13. Pull the battery and power back on while holding the Volume Down button. Once you see the bootloader screen with some text options, cycle through the options using the Volume Down and select "Fastboot Protocol".
14. On the computer, open terminal and run the following command:

    fastboot oem unlock

15. If a message appears claiming that "INFOOEM lock is not implemented", you are done. Otherwise, follow the instructions that appear in your command prompt to unlock your bootloader.

Unlocking the Bootloader with sbf_flash (Linux & OS X)

1. You will need fastboot on the computer to unlock the bootloader of the Motorola Atrix 4G. Follow the Android SDK guide, to get fastboot on the computer.
2. Download sbf_flash and the appropriate unlockable bootloader:
   • sbf_flash: Download
   • AT&T Atrix 4G Only: Unlockable Bootloader: Download

     md5: a5da47565160e0f95b84a1e769b9028b

   • International Variants Only: Unlockable Bootloader: Download

     md5: f609dbc4c5842f9654e44a1980375100

3. Unzip the sbf_flash zipfile.
4. Unzip the bootloader and place it somewhere easy to access.
5. Power off the Motorola Atrix 4G.
6. Boot into RSD Protocol Mode by holding down Up Volume and the Power button.
7. Connect the Motorola Atrix 4G to the computer via USB.
8. On the computer, open terminal and run the following commands:

   chmod +x sbf_flash

   ./sbf_flash <SBF File name here>.sbf

9. It should take a few minutes to flash the unlockable bootloader, and the device may reboot multiple times. Once RSD lite reports that it's finished (or appears to be waiting for the device even though the device is booting into android), the device should be powered off.
10. Pull the battery and power back on while holding the Volume Down button. Once you see the bootloader screen with some text options, cycle through the options using the Volume Down and select "Fastboot Protocol".
11. On the computer, open terminal and run the following command:

    fastboot oem unlock

12. You will now receive a warning along with a unique device ID. Type the following commands using your unique device ID in place of the **ID**:

    fastboot oem unlock **ID**

    fastboot reboot

13. Wait for your device to reboot. Congratulations! You now have an unlocked bootloader!