Hi @DipinPK at the moment, there is not support for Ubuntu on the Raspberry Pi platforms. Our new iteration of the mender-convert tool should allow for easier support of this but it’s not on our planned list of supported OSes at the moment. You can see the current discussion of the new version here :New iteration of the mender-convert tool
And if you would like to get involved in the development, we would happy take a pull request.
Drew