Dual Boot Windows 10 (build 1709) / Sierra 10.12.6 on same single drive (SUCCES)

[cosmos654]

Last builds of Windows 10 UEFI USB installers seem more and more touchy about partitions order/size of target drive.
After many many tries, i successfully installed W10 and Sierra on same drive.

You need:
- 1 USB key with UEFI Windows 10 Installer (https://www.tonymacx86.com/threads/make-a-windows-10-uefi-usb-installer.228959/)
- 1 USB key with Sierra Installer (https://www.tonymacx86.com/resources/unibeast-7-1-1.333/ )
- BIOS must be in UEFI boot mode

- disconnect all other internal/external drives

- boot Windows installer (UEFI) USB
- Shift+F10 for recovery command line
- type: diskpart
- type: list disk
- type: select disk 0 (the target single drive)
- type: clean (you'll loose all data !)
- type: convert gpt
- type: create part msr size=200 (windows 10 doesn’t like EFI partition at first, so I choose MSR)
- type: exit

- install windows 10 on unallocated free space
- once installed, in windows 10 disk manager,
- shrink main NTFS partition as you want (e.g. half the space)
- create new partition on free space just created and format (eg.exFAT format)

- reboot with Sierra USB (Unibeast) installer
- go to Apple Disk Utility (menu)
- reformat exFAT partition with HFS+j
- install Sierra
- that's all

(with the help of this old post from Rehabman: https://www.tonymacx86.com/threads/mavericks-windows-8-on-same-drive-without-erasing.133940/page-2)

 

[tmslacker]

A few more steps are needed, but it works.

I'll post the additional steps - Soon.

 

[jstash]

Do you have the additional steps to share yet?