UEFI Dual Boot Windows 10 and Windows 7 x64 on SSD Drive?

- Win 10 use "Secure boot" that isn't compatible with Win 7. You have to set it to Other and Compatible System Mode to enable. As Win 7 was installed with Secure boot=enable, don't know if it will boot with Secure boot=disabled

For Win 7
Under CSM enable UEFI boot.

More or less like this
OS type Windows UEFI = Secure boot, so if OS type = Other, secure boot is disabled.

for CSM, here are the current settings (in bold)
Launch CSM.......................................(Auto, Enabled, Disabled)
Boot Device Control.............................(UEFI and Legacy OPROM, Legacy OPROM only, UEFI Only)
Boot from Network Devices...................(Ignore, Legacy Only)
Boot from Storage Devices....................(Ignore, Legacy Only, UEFI Driver first)
Boot from PCIe/PCI Expansion Devices....(Legacy Only, UEFI driver first)

Boot from the Win 7 installation disk ON UEFI MODE (important).

Install on the large empty NTFS partition

For the updates MS releases SP2 for Windows 7

Yes, you have to load the m.2 ssd nvme drivers. As you already have added the USB drivers, during installation you can add them from a USB flash disk.
If you want to understand how the drivers affect Win 7 installation disk
Create a Windows 7 USB flash installation with new drives for new MB's

When duel booting you must always install the oldest o/s first as it won't understand new versions boot

Thanks for the reply Megahertz07,

I will give this a try tonight. I am working with a Lenovo y-700 and I have set the bios the exact same way I was able to get windows 7 installed on the regular drive.

samuria said:

When duel booting you must always install the oldest o/s first as it won't understand new versions boot

This is what I always thought was the case as well after research. However I was able to fresh install Windows 10 and then installed Windows 7 on the regular hard drive.

If you were able to install on a regular HDD, you can install on the SSD.
You have to load the m.2 ssd nvme drivers during installation. As you already have added the USB drivers, during installation you can add them from a USB flash disk.

So today I am trying to get this all installed. I installed windows 10 on the ssd, then tried windows 7. Getting a

"The partitions on the disk selected for installation are not in the recommended order. For additional information about installing to GPT disks"

Also turns out my SSD is a MZNTY128HDHP is a SATA M.2 SSD. So no NVMe drives needed.

I have a Z170 MB and a M.2 128G SSD AHCI drive.
I have installed win7 and Win10, in this order.
When installing win7 on the clean SSD, it first created 3 partitions:
- UEFI - 100M Fat32
- MSR - 120M RAW
- Big NTFS.

Before installing win7 I split ed the NTFS partition in two and then installed Win7 on the fist half.
Then installed win10 on the second half.
As it is two windows, during boot it loads the win10 boot loader and asks what windows you want to boot- 10 or 7

On UEFI the boot loader is stored on the UEFI - 100M Fat32 partition, so afterwords I deleted the the Win 10 partition and installed Lubuntu.

"I installed windows 10 on the ssd, then tried windows 7.

As you have Win10 installation disk, try only to install win7 on the M.2 SSD. If you succeed, install win10.