I guess most people will not be aware of boxmode on the HD51, but for those that change it or use the default setup which is currently boxmode=12 to obtain PIP so they can see whats happening on the football (in PIP) whilst the wife watches TV .. things will change in the next build
WIth the introduction of Kodi, the default boxmode will be 1 (no PIP), so you will have to update the STARTUP file (boot/STARTUP) if you want PIP BUT NOT Kodi
If you want both, then you will have to get used to flip flopping the STARTUP file.