NLtrends

When infinix first introduced the android 5.1 lollipop operating
system for the hot note x551 device, one of the basic difficulty
faced is having a computer. Not just a computer, a computer probably
running on windows 7 or windows 10 (windows 8 and 8.1 users gave
complains via comments).
Most users thought the update will be rolled over via OTA but
unfortunately, users would have to flash the ROM to their device via
SP flash tool which certainly involves a computer.
Infinix recently introduced their own flashing tool for those who may
not want to use SP flash tool and yet again, infinix just made it
possible for users to flash the android 5.1 lollipop OS to their hot
note x551 phone via recovery menu without necessarily owing a
computer.
Unfortunately, flashing this ROM to your phone via recovery menu,
leaves your phone not being able to receive OTA update. That way, if
there's an OTA update for the ROM, you would have to manually flash it
in again.
If you feel that's okay for you, save it to the root directory of your
SD-Card and follow the instructions below:
*.Boot into recovery menu by pressing and holding the vol and power
button together
*.When in recovery mode, choose Apply update from SD-Card
*.Select the downloaded file file and choose yes.
When the installation process is complete, reboot your phone by
clicking the reboot system now and there you have it. Please note, as
earlier said, this stock ROM leaves your device not being able to
receive OTA update.