Rashr is a tool that helps you in the process of flashing and backing up the kernel of your Android OS without needing a computer or something extra. The main thing you'll have to understand is that this application works only if you're mobile device is rooted. In case you don't know what rooting means, then you shouldn't "play" with this software because you might ruin the operating system of your tablet/smartphone.
A very big aspect of Rashr is its large collection containing over 6500 build-in recovery images, but the cool thing is that you can also flash images from internal and external storage. The proper way of doing this task is by creating backups of your current kernal and recovery image first. If something goes wrong, you might be able to return to its original state.
The simple user interface has a dedicated section where you can manage all of your backups and the ability to flash them. Another important thing that you'll have to know is that Rashr is capable of working with a huge number of Android devices.