The solarnode-base package includes the Derby database JARs. The solarnode-app-db-h2 switches the database to H2, but the Derby JARs remain. These Derby JARs could be removed, and made part of a solarnode-base-derby package instead, pulled in by the solarnode-app-db-derby package:

app/boot/org.apache.servicemix.bundles.derby-10.12.1.1_1.jar
app/boot/net.solarnetwork.external.org.apache.derby-1.3.0.SN01.jar