EmuELEC internal - CoreELEC external, is it possible?

Well, in fact I know it is doable, I have installed EE 4.6 internally (EMMC) and CE 20 externally (MicroSD).
This way you can take advantage of the 64GB EMMC for roms, and a little-cheap uSD for CoreELEC (and perhaps more roms ;P)

The problem I´m having is when I reboot to Nand from CE it reboots to Android, and the only option I have for runing EE is to turn off the box, unplug the uSD and then turn on the box

Is there any special command or any trick to reboot to EE EMMC from CE uSD???
Perhaps removing Android from EMMC?? although I suppose we need the bootloader from android.
It would be great as you can take advantage of the internal storage and this will be a perfect replacement for the EmuELEC addon (at least for me)

Thanks in advance and thanks for the incredible working you are doing.