Hi keesijp60
I don't quite understand, does your box go to maskrom because you deleted the internal memory? or does it go there on its own, a sign that your internal memory is broken?
Another question, does the multitool tell you that your box has NAND as storage type? Because in that case, you can't install libreelec in the internal memory, but you can only boot it from the SD card. Let me know