Not sure if you managed to fix this? I had the same (ish) issue. I have a BMP (model: M054) already installed in my 2015 car, took it out to update the software (3.0.18) using the BMP Content Manager Software and it turned into a brick! Completely unresponsive.
Bought a new data cable for the mini usb, bought a new battery, reset and reinstalled my pc drivers, tried it on Windows 7 and 10 - no luck! Didn't want to go directly to Becker (as I has seen they are not the most helpful and it can take months), didn't want to buy a new unit, and also didn't want to buy a used one off eBay in case I had the same problem!
Found a company in the UK who claimed to repair the BMP. I was sceptical, but got it in writing that if they couldn't repair it they would send me the unit back and refund me. So I sent it on Tuesday this week, it arrived with them Wednesday and I had it back on Thursday - works a dream, and has all the new maps for Europe etc.
Irritating it went wrong (apparently the new software is too big for the unit, overwrites itself and gets corrupted?!), but I'm so happy it is now fixed and working. The company is Revtronic based in W. Yorkshire - cost me £120 but cheaper than the other alternatives! Also comes with 12 months warranty on the work.