[remlov]

I did something similar, I patched a Gigabyte Z77-DS3H bios with the SAMSUNG_M2_DXE module to get a Samsung SM951 AHCI M.2 SSD working. It's not SATA and not quite NVMe, PCIe AHCI existed for a short while before NVMe became ubiquitous.

This was to enable a screamer of a Hackintosh based on Mavericks which didn't have native NVMe support at the time.

[eqvinox]

> not SATA

> PCIe AHCI

…AHCI is the SATA controller standard, how and why did they put in extra effort to make it not work?!? (I'm not questioning they did in fact break it, it's in line with other dumb things HW vendors do… just… ugh!)

[toast0]

Well m.2 sata would be using one lane as sata with an ahci controller elsewhere (probably embedded in a chipset or cpu).

PCIe AHCI have the controller on the m.2 device, maybe better than sata speeds? But I think to boot from an unexpected AHCI controller you might need a boot rom? And why would you put a boot rom on a device that's all about storage?

[remlov]

My guess is at the time it was a familiar protocol stack which apparently made it easier to retrofit legacy systems before NVMe? AHCI was already well-supported across major OSes then (Windows, Linux, macOS), but UEFI firmware still needed to understand this abomination.