I’ve been using the Micromax Canvas4 from few months. There was an update from Gmail app and I downloaded and installed it. Then It asked me to “AutoSyncOption” to set to “ON” and I clicked “OK”. Later the device was in a restart loop after every 3-4 second. It’s like a mess for me as I bought it recently. Later I had to hard reset the device to factory setting and wiped all the data. Then It worked like a charm. I’ll share the steps but do it at you own risk but it worked for me.
How to Hard Reset the Canvas 4 Android device:
1. Switch off the device and then Boot it with holding volume up + volume down + unlock key together.
2. Now it will start booting when I vibrates first time release the key and It’ll start in the boot mode.
3. Now select the RecoveryMode. You can navigate through the option via volume up & down key and select the option by “Option/Menu” button.
4. It’ll further go to another option menu. Now navigate to select the Wipe user data/Factory Reset option and select ok by Menu key.
5. Now this will start restoring to it’s factory setting*(state of the device when you purchased it).
6. When the reset will finish it’ll go back to the menu again. Now navigate to the Restart the device by selecting Restart option and click ok.
Now your device will be restarted and will be running again.
Warning/Disclaimer: Do this at your own risk. It worked perfectly for me.