Trouble running legato AF on raspberry pi 2

I am facing troubles running legato AF on raspberry pi2, Is it mandatory to rebuild the kernel with legato specific kernel options to run legato on raspberry pi2? As detailed under build platform docs.

Whereas under build apps docs it is advised to use update tool to transfer .update file to raspberry pi2.

Which one to follow and in which sequence?

Please bear the newbie.

Did you see this: How to get started with Legato on Raspberry Pi3 ?

Referring to this link

It is mandatory to rebuild both kernel and Legato framework for Raspbian.
Once Legato framework is running on Raspberry Pi, we should able to use tool provided by Legato framework, i.e. “update” tool to install .update package.

Hope it helps.

Thanx for your help.