Для установки windows нужен оптический дисковод bootcamp

Create a temporary MS-DOS (FAT) formatted partition on the
SSD. You can use the Bootcamp Assistant, the Disk Utility, or
commands (distutil, gpt and/or fdisk) entered in a Terminal
window. Other third party tools, such as gdisk, can also be
used. Give the label for this partition the name «FLASHDRIVE». Since
Apple recommends using a 16 GB flash drive to install Windows 10,
the partition should be at least 16 GB in size. (In practice, this
partition usually can be much smaller.) After Windows 10 is
installed, you can remove this partition and recover the space. This
partition will contain the files from the Windows 10 iso and the
Boot Camp Support Software.

It is my understanding that this temporary partition must occur on the SSD (disk0). If you are able to use the HDD (disk1), please let
me know and I will update these instructions.

Use the Disk Utility application to create a single MS-DOS (FAT)
formatted partition on the HDD. Make sure you use the Master Boot
Record (MBR) partitioning scheme. Name this partition «BOOTCAMP».
This is where Windows 10 will be installed.

If you need to use the GUID Partition Table (GPT) for your partitioning scheme or need additional partitions on the HDD, let me
know.

Quit the Disk Utility.

Set the variables FILE0 and FILE1 to the absolute file names of
the partitions named «FLASHDRIVE and «BOOTCAMP», respectively. To do
this, open a Terminal application window and enter the following
commands.

diskutil  list  disk0;  diskutil  list  disk1

Note: I assume you are using the default Bourne-Again Shell (bash).

The output from the commands should be similar to the following. The
disk identifier for a given disk or partition can be read from the
last column marked «IDENTIFIER». The absolute file name for a
partition can be derived by prepending the string «/dev/» to the
disk identifier.

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *256.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS OS X                    239.7 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data FLASHDRIVE              15.5 GB    disk0s4
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *1.0 TB     disk1
   1:                 DOS_FAT_32 BOOTCAMP                1.0 TB     disk1s1

From the above output, one can deduce the the «FLASHDRIVE» and
«BOOTCAMP» partitions have the disk identifiers «disk0s4» and
«disk1s1», respectively. Using the same Terminal application window,
enter the following assignment statements to set the variables. If
your disk identifiers are different, make the appropriate
substitutions.

FILE0=/dev/disk0s4
FILE1=/dev/disk1s1

Declare the other variables needed for the commands used in the
subsequent steps. To do this, enter the following assignment
statements in the same Terminal application window.

DISK0=$(sed  -n  's/(/dev/disk[0-9]*).*/1/p'<<<$FILE0)
DISK1=$(sed  -n  's/(/dev/disk[0-9]*).*/1/p'<<<$FILE1)
PARTITION0=$(sed  -n  's//dev/disk[0-9]*s(.*)/1/p'<<<$FILE0)
PARTITION1=$(sed  -n  's//dev/disk[0-9]*s(.*)/1/p'<<<$FILE1)

Note: At this point, one should realize it would be easier to copy the statements from this document and paste them into the Terminal
application window.

Enter the following command to view the values of these new
variables. Record your value for the variable DISK1. You will need
to enter it in a later step.

echo  -e  "DISK0=$DISK0nDISK1=$DISK1nPARTITION0=$PARTITION0nPARTITION1=$PARTITION1"

My computer generated the following output.

DISK0=/dev/disk0
DISK1=/dev/disk1
PARTITION0=4
PARTITION1=1

If the value of PARTITION0 is greater than 4, you can not install Windows 10 on the «BOOTCAMP» partition. (Technically, this
is not true. Sent me a comment and I will post how to use
gdisk to overcome this obstacle.)

Using the Finder application, mount the Windows 10 iso file. Copy
the entire contents to root of the partition labeled «FLASHDRIVE».
Afterwards, you can unmount the iso file.

Using the Finder application, copy the Boot Camp Support Software
(BCSS) folder to the root of the partition labeled «FLASHDRIVE».

NOTE: If you open your BCSS folder and find the following file and folders, then instead of coping the BCSS folder, you should
copy these items to the root folder of the partition labeled
«FLASHDRIVE».

$WinPEDriver (folder)
AutoUnattend.xml
BootCamp (folder)

Enter the following command in the same Terminal window.

dot_clean  /Volumes/FLASHDRIVE

Mark the correct partition as active in each disk’s MBR by entering
the following in the same Terminal window. The input for the
interactive command fdisk is taken from the variable INPUT. If
a login password is asked for, enter it.

INPUT=$(printf  "f  $PARTITION0nqny")
sudo  fdisk  -e  $DISK0  <<<"$INPUT";echo
INPUT=$(printf  "f  $PARTITION1nqny")
sudo  fdisk  -e  $DISK1  <<<"$INPUT";echo

Note: To display the value for the variable INPUT, use the
command echo "$INPUT".

Allow VirtualBox read/write access to the physical «FLASHDRIVE»
partition and the entire physical «disk1» by entering the following
commands in the same Terminal application window. If a login
password is asked for, enter it.

 sudo  chmod  go+rw  $FILE0
 sudo  chmod  go+rw  $DISK1*

This will allow VirtualBox to install Windows 10 in your physical
«BOOTCAMP» partition.

Note: This access will only last until OS X is rebooted.

Create the files that map the virtual disk to the physical disk. In
the same Terminal window, enter the following commands. If a login
password is asked for, enter it.

cd  ~/documents/virtualbox
diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1
sudo  vboxmanage  internalcommands  createrawvmdk  -filename  $PWD/SSD.vmdk  -rawdisk  $DISK0  -partitions  $PARTITION0
sudo  chown  $USER  SSD*.vmdk
sudo  vboxmanage  internalcommands  createrawvmdk  -filename  $PWD/HDD.vmdk  -rawdisk  $DISK1
sudo  chown  $USER  HDD.vmdk

Note: OS X prefers to automount file systems. This can be disabled for a particular partition by creating or modifying the
«/etc/fstab» file. Instead of employing the «/etc/fstab» file, the
user is asked to repeatedly enter the following commands.

diskutil unmount $FILE0;diskutil unmountDisk $DISK1

These commands unmount the «FLASHDRIVE» partition and the disk containing the «BOOTCAMP» partition.

Open the VirtualBox application and click on icon above the New
label. Enter or select the values shown below, then click the
«Continue» button.

Use the default settings except for the hard drive. Choose the
«Use an existing virtual hard drive file» button. Navigate to the
VirtualBox folder created in step 5. Highlight the «SSD.vmdk»
file. Before clicking the «Open» button, enter the following
commands in the same Terminal application window.

 diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1

Open the «SSD.vmdk» file. Your window should appear similar to what
is shown below.

Click the «Create» button.

After returning to the VirtualBox application’s «Oracle VM
VirtualBox Manager» window and click on the icon above the
«Settings» label. Next, click on the icon above the «Storage»
label. In the «Storage Tree», «Controller: SATA» should be
highlighted. Right click on this highlighted area and select «Add
Hard Disk». Choose the «Use an existing virtual hard drive file»
button. Navigate to the VirtualBox folder created in step 5.
Highlight the «HDD.vmdk» file. Before clicking the «Open» button,
enter the following commands in the same Terminal application
window.

 diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1

Open the «HDD.vmdk» file. Your window should appear similar to what
is shown below.

Highlight the Empty CD/DVD and select «Choose Virtual Optical Disk
File…» to attach your Windows 10 iso file. (Hint: Look
for the CD/DVD icons)

Click OK to close the window. Your «Oracle VM VirtualBox Manager»
window should appear similar to what is shown below.

Enter the following command in the same Terminal application
window.

 diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1

Next, click on the icon above the «Start» label to boot from the
Windows 10 iso file. Press the space bar when prompted to «Press
any key to boot from CD or DVD.»

Note: The mouse pointer must be over the virtual machine screen window before you press the space bar.

Open a Command Prompt window by clicking on the following sequence.

Next
Repair your computer
Troubleshoot
Advanced options
Command Prompt

The «FLASHDRIVE» partition is drive C:. The «BOOTCAMP» partition is
drive D: and the Optical Drive (DVD) containing the Windows 10 iso
file is drive E:.

Enter the following commands in the Command Prompt window. When
prompted by the command below, enter the volume label «FLASHDRIVE».
This will convert the FAT32 partition to a NTFS partition.

convert  c:  /fs:ntfs

When prompted by the command below, enter the volume label
«BOOTCAMP». This will NTFS format the partition.

format  d: /q  /v:BOOTCAMP

Enter the following command in the Command Prompt window.

bootsect  /nt60  c:
bootsect  /nt60  d:  /mbr

This adds the Bootstrap code to the «FLASHDRIVE» and «BOOTCAMP»
partitions and the MBR of the HDD.

Close the Command Prompt window and click on «Turn off your PC».

After the «BootCamp» virtual machine has «Powered Off», return to
the VirtualBox application’s «Oracle VM Virtual Manager» window.
Click on the icon above the «Settings» label. Next, click on the
icon above the «Storage» label. In the «Storage Tree», right click
on the label «SSD.vmd» and select «Remove Attachment». Your window
should appear similar to what is shown below.

Click the «OK» button to close the window.

From the menu bar select «File→Virtual Media Manager». In the
Virtual Media Manager window, right click on hard disk entry with
the name «SSD.vmdk» and select «Remove». If prompted with
confirmation pop up, click the «Remove» button. In the pop with
with the choices «Cancel», «Keep» and «Delete», choose «Keep». Your
window should appear similar to what is shown below.

Click the «Close» button to close the window, and then quit the
VirtualBox application.

Enter the following command in the same Terminal application
window. If prompted, enter your login password. This command
copies the Bootstrap code from the MBR of the HDD to the MBR of the
SSD.

sudo  fdisk  -u  -y  -f  $DISK1  $DISK0

Enter the following in the same Terminal application window. This
will enter the correct partition type in the MBR partition table
for the FLASHDRIVE partition.

 INPUT=$(printf  "s  $PARTITION0n7nqny")
 fdisk  -e  $DISK0  <<<"$INPUT";echo

Enter the following command in the same Terminal application
window. If a login password is asked for, enter it.

 sudo  bless  --device  $DISK0  --setBoot  --legacy

This instructs the computer that subsequent boots should be
performed in legacy BIOS mode from the internal SSD.

Close all applications and windows. If you intend to use Audit
mode during the installation of Windows and the computer is
hardwired to the internet, then disconnect the computer from the
internet now. Restart the computer and start installing Windows
10 into the BOOTCAMP partition.

When you reach the window shown below, select «Custom (advanced)».

When you reach the window show below, select the «BOOTCAMP»
partition. Do not format the «BOOTCAMP» partition. Click the
«Next» button.

If do not intend to use Audit mode, the you can skip this step. To use Audit mode, follow the steps given in my answer to the
question: How to prevent Windows 10 from downloading and
installing updates before the Boot Camp Support Software is
installed? While in Audit mode, if you need to access the Boot
Camp Support Software (BCSS) stored in the «FLASHDRIVE» partition,
then follow the instructions given in the rest of this step.

First, make sure you are in Audit mode as explained in the above
hyperlink. Next, right click on the Start button on the taskbar and
select «Disk Management», as shown below.

Right click on the «FLASHDRIVE» partition and select «Change Drive
Letter and Paths…», as shown below. Assign the partition the
drive letter S:. When finished, close the «Disk Management» window.

You now have access to the Boot Camp Support Software on drive S:.
Before exiting the Audit mode, remove drive letter S: from the «FLASHDRIVE» partition. When removing, ignore the warning
messages.

Finish installing Windows 10. Once finished, locate the «Boot Camp»
icon on the system tray in the Windows taskbar. Right click on the
«Boot Camp» icon and select «Restart in Mac OS X», as shown below.
Note: This may appear sightly different if you installed a
different version of the Boot Camp Support Software (BCSS) than I
did.

Once finished restarting in OS X, assign the variable DISK1 the
value recorded in an earlier step. To do this, first open the
Terminal application and enter the following assignment statement
in the new window. If you recorded a different value, make the
appropriate substitution.

  DISK1=/dev/disk1

Allow VirtualBox read/write access to the entire physical «disk1» by
entering the following command in the same Terminal application
window. If a login password is asked for, enter it.

sudo  chmod  go+rw  $DISK1*    

This will allow VirtualBox to create Boot Configuration Data (BCD)
store in your physical «BOOTCAMP» partition.

Note: This access will only last until OS X is rebooted.

Enter the following command in the same Terminal application
window.

  diskutil  unmountDisk  $DISK1

Next, open the VirtualBox application to view the «Oracle VM
VirtualBox Manager» window.

Enter the following command in the same Terminal application
window.

 diskutil  unmountDisk  $DISK1

Next, click on the icon above the «Start» label to boot from the
Windows 10 iso file. Press the space bar when prompted to «Press
any key to boot from CD or DVD.»

Note: The mouse pointer must be over the virtual machine screen window before you press the space bar.

Open a Command Prompt window by clicking on the following sequence.

Next
Repair your computer
Troubleshoot
Advanced options
Command Prompt

The «BOOTCAMP» partition is drive C: and the Optical Drive (DVD)
containing the Windows 10 iso file is drive D:.

Enter the following commands in the Command Prompt window to build
a Boot Configuration Data (BCD) store in the «BOOTCAMP» partition.
When prompted enter the letter «y». This will create the file
«C:BootBCD».

 cd  /d  c:
 bootrec  /rebuildbcd

Note: The directory «Boot» has the file attributes «Hidden» and «System».

The results from entering the above two commands is shown below.

Close the Command Prompt window and click on «Turn off your PC».

Create a temporary MS-DOS (FAT) formatted partition on the
SSD. You can use the Bootcamp Assistant, the Disk Utility, or
commands (distutil, gpt and/or fdisk) entered in a Terminal
window. Other third party tools, such as gdisk, can also be
used. Give the label for this partition the name «FLASHDRIVE». Since
Apple recommends using a 16 GB flash drive to install Windows 10,
the partition should be at least 16 GB in size. (In practice, this
partition usually can be much smaller.) After Windows 10 is
installed, you can remove this partition and recover the space. This
partition will contain the files from the Windows 10 iso and the
Boot Camp Support Software.

It is my understanding that this temporary partition must occur on the SSD (disk0). If you are able to use the HDD (disk1), please let
me know and I will update these instructions.

Use the Disk Utility application to create a single MS-DOS (FAT)
formatted partition on the HDD. Make sure you use the Master Boot
Record (MBR) partitioning scheme. Name this partition «BOOTCAMP».
This is where Windows 10 will be installed.

If you need to use the GUID Partition Table (GPT) for your partitioning scheme or need additional partitions on the HDD, let me
know.

Quit the Disk Utility.

Set the variables FILE0 and FILE1 to the absolute file names of
the partitions named «FLASHDRIVE and «BOOTCAMP», respectively. To do
this, open a Terminal application window and enter the following
commands.

diskutil  list  disk0;  diskutil  list  disk1

Note: I assume you are using the default Bourne-Again Shell (bash).

The output from the commands should be similar to the following. The
disk identifier for a given disk or partition can be read from the
last column marked «IDENTIFIER». The absolute file name for a
partition can be derived by prepending the string «/dev/» to the
disk identifier.

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *256.0 GB   disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS OS X                    239.7 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
   4:       Microsoft Basic Data FLASHDRIVE              15.5 GB    disk0s4
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *1.0 TB     disk1
   1:                 DOS_FAT_32 BOOTCAMP                1.0 TB     disk1s1

From the above output, one can deduce the the «FLASHDRIVE» and
«BOOTCAMP» partitions have the disk identifiers «disk0s4» and
«disk1s1», respectively. Using the same Terminal application window,
enter the following assignment statements to set the variables. If
your disk identifiers are different, make the appropriate
substitutions.

FILE0=/dev/disk0s4
FILE1=/dev/disk1s1

Declare the other variables needed for the commands used in the
subsequent steps. To do this, enter the following assignment
statements in the same Terminal application window.

DISK0=$(sed  -n  's/(/dev/disk[0-9]*).*/1/p'<<<$FILE0)
DISK1=$(sed  -n  's/(/dev/disk[0-9]*).*/1/p'<<<$FILE1)
PARTITION0=$(sed  -n  's//dev/disk[0-9]*s(.*)/1/p'<<<$FILE0)
PARTITION1=$(sed  -n  's//dev/disk[0-9]*s(.*)/1/p'<<<$FILE1)

Note: At this point, one should realize it would be easier to copy the statements from this document and paste them into the Terminal
application window.

Enter the following command to view the values of these new
variables. Record your value for the variable DISK1. You will need
to enter it in a later step.

echo  -e  "DISK0=$DISK0nDISK1=$DISK1nPARTITION0=$PARTITION0nPARTITION1=$PARTITION1"

My computer generated the following output.

DISK0=/dev/disk0
DISK1=/dev/disk1
PARTITION0=4
PARTITION1=1

If the value of PARTITION0 is greater than 4, you can not install Windows 10 on the «BOOTCAMP» partition. (Technically, this
is not true. Sent me a comment and I will post how to use
gdisk to overcome this obstacle.)

Using the Finder application, mount the Windows 10 iso file. Copy
the entire contents to root of the partition labeled «FLASHDRIVE».
Afterwards, you can unmount the iso file.

Using the Finder application, copy the Boot Camp Support Software
(BCSS) folder to the root of the partition labeled «FLASHDRIVE».

NOTE: If you open your BCSS folder and find the following file and folders, then instead of coping the BCSS folder, you should
copy these items to the root folder of the partition labeled
«FLASHDRIVE».

$WinPEDriver (folder)
AutoUnattend.xml
BootCamp (folder)

Enter the following command in the same Terminal window.

dot_clean  /Volumes/FLASHDRIVE

Mark the correct partition as active in each disk’s MBR by entering
the following in the same Terminal window. The input for the
interactive command fdisk is taken from the variable INPUT. If
a login password is asked for, enter it.

INPUT=$(printf  "f  $PARTITION0nqny")
sudo  fdisk  -e  $DISK0  <<<"$INPUT";echo
INPUT=$(printf  "f  $PARTITION1nqny")
sudo  fdisk  -e  $DISK1  <<<"$INPUT";echo

Note: To display the value for the variable INPUT, use the
command echo "$INPUT".

Allow VirtualBox read/write access to the physical «FLASHDRIVE»
partition and the entire physical «disk1» by entering the following
commands in the same Terminal application window. If a login
password is asked for, enter it.

 sudo  chmod  go+rw  $FILE0
 sudo  chmod  go+rw  $DISK1*

This will allow VirtualBox to install Windows 10 in your physical
«BOOTCAMP» partition.

Note: This access will only last until OS X is rebooted.

Create the files that map the virtual disk to the physical disk. In
the same Terminal window, enter the following commands. If a login
password is asked for, enter it.

cd  ~/documents/virtualbox
diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1
sudo  vboxmanage  internalcommands  createrawvmdk  -filename  $PWD/SSD.vmdk  -rawdisk  $DISK0  -partitions  $PARTITION0
sudo  chown  $USER  SSD*.vmdk
sudo  vboxmanage  internalcommands  createrawvmdk  -filename  $PWD/HDD.vmdk  -rawdisk  $DISK1
sudo  chown  $USER  HDD.vmdk

Note: OS X prefers to automount file systems. This can be disabled for a particular partition by creating or modifying the
«/etc/fstab» file. Instead of employing the «/etc/fstab» file, the
user is asked to repeatedly enter the following commands.

diskutil unmount $FILE0;diskutil unmountDisk $DISK1

These commands unmount the «FLASHDRIVE» partition and the disk containing the «BOOTCAMP» partition.

Open the VirtualBox application and click on icon above the New
label. Enter or select the values shown below, then click the
«Continue» button.

Use the default settings except for the hard drive. Choose the
«Use an existing virtual hard drive file» button. Navigate to the
VirtualBox folder created in step 5. Highlight the «SSD.vmdk»
file. Before clicking the «Open» button, enter the following
commands in the same Terminal application window.

 diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1

Open the «SSD.vmdk» file. Your window should appear similar to what
is shown below.

Click the «Create» button.

After returning to the VirtualBox application’s «Oracle VM
VirtualBox Manager» window and click on the icon above the
«Settings» label. Next, click on the icon above the «Storage»
label. In the «Storage Tree», «Controller: SATA» should be
highlighted. Right click on this highlighted area and select «Add
Hard Disk». Choose the «Use an existing virtual hard drive file»
button. Navigate to the VirtualBox folder created in step 5.
Highlight the «HDD.vmdk» file. Before clicking the «Open» button,
enter the following commands in the same Terminal application
window.

 diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1

Open the «HDD.vmdk» file. Your window should appear similar to what
is shown below.

Highlight the Empty CD/DVD and select «Choose Virtual Optical Disk
File…» to attach your Windows 10 iso file. (Hint: Look
for the CD/DVD icons)

Click OK to close the window. Your «Oracle VM VirtualBox Manager»
window should appear similar to what is shown below.

Enter the following command in the same Terminal application
window.

 diskutil  unmount  $FILE0;diskutil  unmountDisk  $DISK1

Next, click on the icon above the «Start» label to boot from the
Windows 10 iso file. Press the space bar when prompted to «Press
any key to boot from CD or DVD.»

Note: The mouse pointer must be over the virtual machine screen window before you press the space bar.

Open a Command Prompt window by clicking on the following sequence.

Next
Repair your computer
Troubleshoot
Advanced options
Command Prompt

The «FLASHDRIVE» partition is drive C:. The «BOOTCAMP» partition is
drive D: and the Optical Drive (DVD) containing the Windows 10 iso
file is drive E:.

Enter the following commands in the Command Prompt window. When
prompted by the command below, enter the volume label «FLASHDRIVE».
This will convert the FAT32 partition to a NTFS partition.

convert  c:  /fs:ntfs

When prompted by the command below, enter the volume label
«BOOTCAMP». This will NTFS format the partition.

format  d: /q  /v:BOOTCAMP

Enter the following command in the Command Prompt window.

bootsect  /nt60  c:
bootsect  /nt60  d:  /mbr

This adds the Bootstrap code to the «FLASHDRIVE» and «BOOTCAMP»
partitions and the MBR of the HDD.

Close the Command Prompt window and click on «Turn off your PC».

After the «BootCamp» virtual machine has «Powered Off», return to
the VirtualBox application’s «Oracle VM Virtual Manager» window.
Click on the icon above the «Settings» label. Next, click on the
icon above the «Storage» label. In the «Storage Tree», right click
on the label «SSD.vmd» and select «Remove Attachment». Your window
should appear similar to what is shown below.

Click the «OK» button to close the window.

From the menu bar select «File→Virtual Media Manager». In the
Virtual Media Manager window, right click on hard disk entry with
the name «SSD.vmdk» and select «Remove». If prompted with
confirmation pop up, click the «Remove» button. In the pop with
with the choices «Cancel», «Keep» and «Delete», choose «Keep». Your
window should appear similar to what is shown below.

Click the «Close» button to close the window, and then quit the
VirtualBox application.

Enter the following command in the same Terminal application
window. If prompted, enter your login password. This command
copies the Bootstrap code from the MBR of the HDD to the MBR of the
SSD.

sudo  fdisk  -u  -y  -f  $DISK1  $DISK0

Enter the following in the same Terminal application window. This
will enter the correct partition type in the MBR partition table
for the FLASHDRIVE partition.

 INPUT=$(printf  "s  $PARTITION0n7nqny")
 fdisk  -e  $DISK0  <<<"$INPUT";echo

Enter the following command in the same Terminal application
window. If a login password is asked for, enter it.

 sudo  bless  --device  $DISK0  --setBoot  --legacy

This instructs the computer that subsequent boots should be
performed in legacy BIOS mode from the internal SSD.

Close all applications and windows. If you intend to use Audit
mode during the installation of Windows and the computer is
hardwired to the internet, then disconnect the computer from the
internet now. Restart the computer and start installing Windows
10 into the BOOTCAMP partition.

When you reach the window shown below, select «Custom (advanced)».

When you reach the window show below, select the «BOOTCAMP»
partition. Do not format the «BOOTCAMP» partition. Click the
«Next» button.

If do not intend to use Audit mode, the you can skip this step. To use Audit mode, follow the steps given in my answer to the
question: How to prevent Windows 10 from downloading and
installing updates before the Boot Camp Support Software is
installed? While in Audit mode, if you need to access the Boot
Camp Support Software (BCSS) stored in the «FLASHDRIVE» partition,
then follow the instructions given in the rest of this step.

First, make sure you are in Audit mode as explained in the above
hyperlink. Next, right click on the Start button on the taskbar and
select «Disk Management», as shown below.

Right click on the «FLASHDRIVE» partition and select «Change Drive
Letter and Paths…», as shown below. Assign the partition the
drive letter S:. When finished, close the «Disk Management» window.

You now have access to the Boot Camp Support Software on drive S:.
Before exiting the Audit mode, remove drive letter S: from the «FLASHDRIVE» partition. When removing, ignore the warning
messages.

Finish installing Windows 10. Once finished, locate the «Boot Camp»
icon on the system tray in the Windows taskbar. Right click on the
«Boot Camp» icon and select «Restart in Mac OS X», as shown below.
Note: This may appear sightly different if you installed a
different version of the Boot Camp Support Software (BCSS) than I
did.

Once finished restarting in OS X, assign the variable DISK1 the
value recorded in an earlier step. To do this, first open the
Terminal application and enter the following assignment statement
in the new window. If you recorded a different value, make the
appropriate substitution.

  DISK1=/dev/disk1

Allow VirtualBox read/write access to the entire physical «disk1» by
entering the following command in the same Terminal application
window. If a login password is asked for, enter it.

sudo  chmod  go+rw  $DISK1*    

This will allow VirtualBox to create Boot Configuration Data (BCD)
store in your physical «BOOTCAMP» partition.

Note: This access will only last until OS X is rebooted.

Enter the following command in the same Terminal application
window.

  diskutil  unmountDisk  $DISK1

Next, open the VirtualBox application to view the «Oracle VM
VirtualBox Manager» window.

Enter the following command in the same Terminal application
window.

 diskutil  unmountDisk  $DISK1

Next, click on the icon above the «Start» label to boot from the
Windows 10 iso file. Press the space bar when prompted to «Press
any key to boot from CD or DVD.»

Note: The mouse pointer must be over the virtual machine screen window before you press the space bar.

Open a Command Prompt window by clicking on the following sequence.

Next
Repair your computer
Troubleshoot
Advanced options
Command Prompt

The «BOOTCAMP» partition is drive C: and the Optical Drive (DVD)
containing the Windows 10 iso file is drive D:.

Enter the following commands in the Command Prompt window to build
a Boot Configuration Data (BCD) store in the «BOOTCAMP» partition.
When prompted enter the letter «y». This will create the file
«C:BootBCD».

 cd  /d  c:
 bootrec  /rebuildbcd

Note: The directory «Boot» has the file attributes «Hidden» and «System».

The results from entering the above two commands is shown below.

Close the Command Prompt window and click on «Turn off your PC».