Somebody told me to try this method using an USB to install Bootcamp, because it wouldn't work for my 2017 Mojave Fusion drive iMac. I haven't actually tried it yet, but is there anything in there that you might add to?
- Open BootCamp and download the Bootcamp drivers for Windows. Action > download drivers.
- Plug in a USB and launch disk utility. Then format it as ms-dos fat. Name it Bootcamp (or Win10 or whatever you want really).
- Next, download unetbootin and the Win 10 ISO so we can make a USB installer. If you don’t know which disk the USB is, open terminal and type diskutil list [name of drive].
- Open unetbootin and then click disk image, set it to ISO and then click the three dots to navigate to then Windows image.
- Then set type to USB drive and then select the disk path (this is the path you got from terminal command). Then make the bootable USB.
- Next, open disk utility and then add a partition. Set the size to what you want. Make sure it is ms-dos fat and name it BOOTCAMP.
- Once USB is done, put Bootcamp drivers on it (drop anywhere, Win installer will ignore them) and restart Mac and then hold down the option key at boot.
- Choose UEFI boot from the menu. Follow Windows prompts until you get to the step where it asks for where you want to install Windows. Select the BOOTCAMP partition. Click delete. It’ll turn into unallocated. Then click new. Accept all prompts.
- Once you load into Windows, open the USB drive and then run the Bootcamp driver installer to get wireless and all that good stuff.