You don't have to burn a CD. It's possible to boot from Pegasos 2 OF directly from morphos.iso using boot.img parameter bootimage (bi).
bootimage=x (bi=x) - allows to boot from a MorphOS .iso without burning it on a CD media. expects a full path to an .iso file. The .iso file must be placed on a disk that's accessible with the builtin filesystems: FFS, SFS, Fat
It will boot new MorphOS version from ISO :)
File boot.img from ISO (CD) should be used to boot so you will have ROM kernel and data from the same MorphOS version.