Same problem here.
I think it could be related to WBM: I did a fresh installation of windows 10 on a ssd and everything was fine. Than, after a few days, I formatted the emmc drive (that still had the boot manager and the recovery on it, before I formatted it) and since that day the bios doesn’t even see the emmc norĀ the ssd.
I want to try to fix the WBM, but I don’t have my windows USB stick with me right now. I will try tomorrow night and let you know.