How to add layer(bblayer) in rpb build for dragon board

how to add layer(bblayer) in rpb build for dragon board

When you performed initial setup, you can simply locally add your layer to BBLAYERS variable in build-rpb/conf/bblayers.conf

Just in case you want to create your own custom RPB manifest/repo, configuration files (local.conf, bblayers.conf) are retrieved from .repo/manifests/conf/bblayers.conf