How can EMR cluster with ubuntu custom image be created?

Need to create an emr cluster with custom ubuntu image. While I tried to use market place ubuntu image to create the cluster, I got an error stating that EMR cluster can not be created with multiple EBS volumes. However the image has the single mount point with multiple partitions. After debugging I figured out that all the ubuntu base images come with multiple partitions in a single mounting point. So need to know how can I create an EMR cluster with ubuntu as a image.