Hi Taxi,
I have been running a Supernova M99 front light for over 12 months on my Gen 4 Bosch motor via the regular light output. It is annoying that it cuts the power to the motor at 10% battery...
The light ports are not live unless the function is enabled via a bosch dealer, i have tested this with a multimeter.
I just started a thread in the general section asking about running the front and rear lights from the "third-party power port" and disabling the light function on the computer:
See thread HERE
I have ordered the cable, it should be with me tomorrow. The only caveat being both front and rear lights will need their own switch. I use a Lupine C14 on the rear which has it's own button.
I'll let you know how I get on.