I was updating my Bootcamp windows 10 (which was running in Parallels Desktop). Something happened apparently (I don't know what), and when I later started the Bootcamp Windows from Parallels, its boot failed and asked me to insert the Windows installation disk and use a startup recovery option. I did this, and it didn't help. I read some guides on the net, and finally I formatted the EFI partition, and ran bcdboot to recreate the boot loader. This failed. What can I do to repair the boot loader?