I 've installed the Mediatek driver correctly (in my opinion). After deinstall (leaving the driver in the system!), reboot and connecting the (turned off) phone, I got the message, the USB-device is not installed correctly. The device-manager shows the Mediatek preloader com port only for a moment, ...
Still working: https://www.amazon.de/UGREEN-Ladeadapter-Wandladeger%C3%A4t-Intelligent-Technologie/dp/B00R25QZDC/ref=sr_1_27_sspa?ie=UTF8&qid=1518522417&sr=8-27-spons&keywords=ladeger%C3%A4t+blackview&psc=1 - but not fast. Just testet with BV8000pro Not testet: https://www.amazon.de/...