Android One Micromax Canvas A1 update to Android 5.1

1. Download this update zip file and place it in your memory card:
http://ota.googlezip.net/packages/ot...6.d827aed7.zip

2. If you haven't flashed any custom recovery, you're good to go.
Else flash the stock recovery. Link: http://www.mediafire.com/?cr10jbo9f6gnh32
Now switch off your mobile and hold power button + volume up button until you get the (boot loader) menu.

3. Then use the volume up button and point to the recovery option.
Then press the volume down button.

4. You'll now see a bot lying down with !
Now hold power button + tap the volume up button once.
You'll now see a menu. (If you for get the menu, try the combination again)

5. Head to the "Install update from SD Card" using volume down button and select it using power button. Select the zip file you downloaded using the volume up or down keys and choose it by pressing power button.

6. That's it! Now select the "reboot system option" and wait for a few minutes to let the phone boot. Now you're ready to go with lollipop 

Refer :- http://forum.xda-developers.com/canvas-a1/help/info-lollipop-5-0-update-t2908384/page226