Complex sentence: Therefore such devices have software systems in ROM or flash memory so the device can begin functioning immediately; little or no loading is necessary, because the loading can be precomputed and stored on the ROM when the device is made.
Split into simpler sentences: Therefore such devices have software systems in ROM or flash memory so the device can begin functioning immediately. For these types of embedded system little or no loading is necessary, since the loading can be precomputed and stored on the ROM when the device is made.