Install Windows with 'Boot' Partition on different drive

Here's the situation. I have a Lenovo Edge E531 laptop which has a 2.5" SATA3 bay and an M.2 SATA3 slot.
The M.2 slot is meant for the OEM config option of having a cache SSD which I don't have.
I DO NOT know if you can boot from an SSD connected to the M.2 slot. Hence me asking here before purchasing the M.2 SSD.

Can I install Windows with the 'boot' partition on the main HDD, that simply points to all the 'Windows' and 'Program Files' files on the M.2 SSD (which appears as a normal drive to the system, just unsure if the firmware can boot from it).

Hope I explained it well enough.

Not familar with such a laptop with dedicated "slots" for an MSATA* where SSD chip is only to provide cache. Does it have a SATA connector in the bay? If so and it fits a normal SSD drive then I don't know why it wouldn't allow install and boot from Win7 onto the SSD.

As to your question if it is necessary to place the boot files on the HD with OS and programs installed on the SSD, it should be but I doubt it would be necessary. You should remove or disable the HD in BIOS to install Win7 onto the SSD, then afterwards re-enable the HDD to move onto it the User Folders - Change Default Location.

Let us know how this goes.

Install Windows on System with MSATA and ISRT - Windows 7 Help Forums
Install Windows on MSATA (SSD) Drive - Windows 7 Help Forums

It is not an mSATA or an M.2 PCI-E port. It is an M.2 SATA3 port, quite common nowadays in business or gaming laptops and Z97 motherboards..

My question wasn't whether it was necessary to place the boot partition* on the HDD, we don't know the answer to that yet.

My question was whether you CAN do this. I know that Windows 7 boots from a ~100MB partition which loads the OS off the main partition.

I specifically answered your question that the boot files should be able to be placed on another disk though it may require Legacy install over UEFI or other workarounds, many of which were developed here.

If need be we can show you how since no other site has managed tens of thousands of these complex partitioning and boot configuration cases without a single failure.

But first I would study your Manual, contact tech support included in any PC purchase for one year if still available, and do all other research to know how this config is meant to be reinstalled. Normally boot files go on the SSD to speed boot.

gregrocker said:

I specifically answered your question that the boot files should be able to be placed on another disk though it may require Legacy install over UEFI or other workarounds, many of which were developed here.

If need be we can show you how since no other site has managed tens of thousands of these complex partitioning and boot configuration cases without a single failure.

But first I would study your Manual, contact tech support included in any PC purchase for one year if still available, and do all other research to know how this config is meant to be reinstalled. Normally boot files go on the SSD to speed boot.

I am sorry but your post was confusing since you were stating mSATA.

Lenovo may have not allowed booting from an M.2 SSD as they are known to do things like this. (They have whitelisted WiFi cards too)

I just want to know whether it IS possible or not at all. No need to go to the trouble of detailing it as I haven't purchased the M.2 SSD yet.

It's not possible to say to sure without knowing how the BIOS and drives are configured. I would want to know everything about such a drives potential and possible uses starting with Lenovo.

When you search the model is this the only help thread that comes up? Ask Lenovo to help fill in the info you and other owners need. Is it in the Manual?