These are the instructions to root Micromax A90 (running on android 4.0.3) using Framaroot App.
Requirements: Your Micromax A90 smartphone should have at least 10-20 percent battery to perform the rooting process.
Root Micromax A90
- Enable installation of 3 party Apps on your Micromax A90. To Enable, Open Settings > Security > Device Administration >Unknown Sources > Tap on the Checkbox to enable it.
- Download and install Framaroot App on the Device. Once you have successfully installed the Framaroot App on the device, then you will be able to see the Framaroot Icon in the App Drawer.
- Now, Tap on the Framaroot App Icon to Open it:
- Once Framaroot App is launched, you will be able to see the following screen on the Device:
- Tap on any of the available Exploits (exploits name may vary per device) to Root the Device. If an exploit fails to root the device, then try the other one.
- Once your Device is Rooted, then you will be able to see the Success Message on the Screen.
- Restart the Device.
- Now your device is Rooted. To check whether your phone is rooted correctly, Open App Drawer, you will be able to see a new app installed, called SuperSU. If this app exists, then it means your device is successfully rooted.
Optional: You can also verify the root status of your device by using the Root Checker App.
 No data loss process: Your Micromax A90 Phone Data like contacts, pictures, videos, music and etc will be not affected with the above method.
 Micromax Stock Firmware: If you are looking for the original Stock Firmware, then head over to the Micromax Stock Firmware page.
 Micromax USB Driver: If you are looking for the original usb driver then head over to the Download Micromax USB Driver page.
 Credits: Framaroot App is created and distributed by Alephzain (XDA Developer). So, full credit goes to him for sharing the app for free.