Question BIOS mod to allow use of NVMe SSD as legacy boot drive ?

[nollyss]

Hi,

I have updated the BIOS on my Asus P8Z77-VPRO mobo using a modded file to allow my PCIe NVMe card with NVMe SSD attached to be recognised as a boot disk in UEFI bios. This works fine when booting in UEFI mode and Windows loads up without problems.

But when I try a different NVMe SSD that has been converted to legacy bios mode with Windows installed on the NVMe SSD, the PCIe card is not recognised as this in the BIOS, all that shows up is PATA SS.

What is the issue, is it the motherboard not suporting legacy boot on NVMe SSD, or the PCIe NVMe card which is the 4 Port HighPoint Rocket 1204 NVMe Card, 4x M.2 NVMe Ports, PCIe 3.0 x16?
Or is it the NVMe SSD card not supporting Legacy bios boot?

I have tried changing a number of options in the BIOS without any luck, not sure if I may have missed something or it is just the motherboard not supporting legacy boot mode in bios on NVMe SSD in PCIe card.
Any help appreciated.

 

[BFG-9000]

NVMe boot requires UEFI mode, without it the module is not loaded. And for Windows, MBR boot isn't supported in UEFI mode either, GPT required.

 

[SkyNetRising]

NVMe boot requires UEFI mode, without it the module is not loaded. And for Windows, MBR boot isn't supported in UEFI mode either, GPT required.

Not true. It's perfectly possible to boot from NVME drive in legacy mode.
BIOS needs to support booting from PCIE device though.

For those old boards (without native support for PCIE boot)
you can put bootloader on some small sata drive and
put windows OS partition on NVME drive.

 

[SkyNetRising]

What is the issue, is it the motherboard not suporting legacy boot on NVMe SSD, or the PCIe NVMe card which is the 4 Port HighPoint Rocket 1204 NVMe Card, 4x M.2 NVMe Ports, PCIe 3.0 x16?

That card most likely requires a driver.
If you're trying to use nvme drive from a different computer, driver has to be installed before moving nvme drive to this adapter.

Also it's generally not recommended to use OS drive from a different computer.
You get several issues, when transplanting OS drive this way.

boot compatibility issues - system doesn't boot,​

driver compatibility issues - bsods crashes, bad performance,​

windows activation issues - not possible to activate windows.​

 

[BFG-9000]

Well sure, Legacy Boot just requires BIOS support and an option ROM in the NVMe drive to essentially make it show up as like a SCSI drive, and the last one that had that was the old Samsung 950 Pro. They don't make those anymore and it is very unlikely for anyone to bother with adding NVMe Legacy module support in a modded BIOS for a Sandy/Ivy Bridge board from years before the first ever NVMe drive was made.

In NVMe the option ROM must be in the drive, not the card. And while the driver should load fine once in Windows if you want to use it as a storage drive, you can't boot from it without the above or a workaround, like a bootloader on the mentioned SATA drive or a USB stick (Clover, rEFInd, DEUT). In which case you're really booting from that, not the NVMe.