I used this video guide to run wire from my dashcam Blackvue DR650s front/back cams from the rearview mirror to the battery in the trunk. He's using a Thinkware dashcam, I'm using a Blackvue but it worked perfectly for me. I did not put any of the inline fuses on the wire that he recommends though.
https://f87.bimmerpost.com/forums/sh....php?t=1378415