How to start Bootloader and System Recovery Mode for Android Users
If you’re having any problem with your android-enabled mobile phones, you can start the bootloader or go to the System Recovery Mode. A person may have a different version of bootloader, because of varied Android OS versions and the varied models of phones, but that will not pose any problem.
Bootloader mode can be opted for viewing your bootloader version or flashing new SBF. If your phone comes with a QWERTY keyboard, the method described below will be applicable.
First of all, by keeping the Power button pressed for a while, shut down your handset and select Power Off. From here, you can either go for pressing and holding the Up arrow key on the D-pad and after that unless the screen is lighted, press the Power key, or press and hold the Camera key and the Volume Down button together and then until the screen gets lighted, continue pressing of the Power button. The screen will show the same or similar text to the following:
Bootloader
<version number>
Battery OK
OK to Program
Connect USB
Data Cable
Your handset now has come into the bootloader mode. It’ll show “Transfer Mode: USB” if the USB cable is pre-plugged into it.
On the other hand, you may wish to access the System Recovery Mode of Android. This may be to wipe certain data, to erase cache partition, restore factory settings, or to apply update.zip on your SD card in order to root the handset for administrative access. Please note that this guide might not be applicable for all Android devices, but it should work for Motorola Droid and Motorola Milestone.
So, here also, you will, first of all, have to shut down your handset by keeping the Power button pressed for some time and choose Power Off. Thereafter, X key of the QWERTY keyboard has to be pressed and held and keep the Power button pressed on as long as the screen gets lighted.
As soon as the Motorola logo comes in view, let go the Power button, but hold on to the X key unless a triangle with an exclamation mark comes out. Or, on the other hand, you can keep the Camera button pressed and hold alongside the Power button until the screen gets lighted. Here also, as soon as the Motorola logo comes into view, let go the Power button, but hold on to the Camera button till the very same triangular icon with the exclamation mark comes into view.
Now press & hold jointly the Camera buttons and Volume Up in order to get the System Recovery menu. To scroll through the menu and opt for the preferred action, make use of the D-pad.
Note: Only users who are properly aware of these functions should attempt this.

