It’s an inevitable part of the Android hacking process that you will ‘soft brick’ your device from time to time. Normally these are pretty trivial problems, the device gets stuck in a boot loop for example.
And normally you can fix them by wiping your data and cache and then
reflashing your ROM, or just by restoring your android backup.
But sometimes the problem can be harder to diagnose.
Maybe your custom Recovery was
accidentally overwritten with the stock one, which has no advanced features. Or maybe you
can’t boot into Recovery at all.
Well, there’s still a solution for most devices. It’s called Fastboot. This is a feature of the
Android software development kit (SDK) and enables you to communicate with your device
when it is connected to your desktop computer via USB.
In Fastboot you can flash a new
custom Recovery, or flash a new ROM itself and wipe the device completely and
return it to stock if needed.
Fastboot is available on most Android devices, excluding Samsung where it
is not implemented.
For a Galaxy device you need to use the Odin tool to
flash a new ROM or Recovery (the unofficial site samsung-updates.com
normally has the latest version available to download).
On Nexus and
HTC devices Fastboot is an invaluable tool, and can be a phone saver.
Using Fastboot step by step guides