Complex sentence: This has the advantage or requiring minimal additional engineering, because the LCD itself is unmodified, retaining the reflective backing of an unlit system; ergo, if conditions warrant, the front light can be deactivated and the LCD can still retain useful visibility.
Split into simpler sentences: This has the advantage or requiring minimal additional engineering, because the LCD itself is unmodified. It also retains the reflective backing of the original LCD, so that if conditions warrant, the front light can be deactivated and the LCD can still retain useful visibility.