When the largest bike sharing operator in my town left I received as a gift a few black boxes, both literally and figuratively. Even though the device MCU was without any identificaton marking, I finally was able to identify it and reverse engineer the PCB and the firrmware. This led to reuse of the devices as educative platforms (at least for me) and as anti-theft car GPSs.
In the original firmware you can find a string containing coordinate expressed according to the NMEA standard (2237.75314,N,11408.62621,E). The point to somewhere in Shenzen 1500m from the site of Omni Intelligent Technology Co.