I ended up using ImageBuilder to make custom ESXi ISO
I ran PowerCLI in RemoteSigned execution
For the Samsung SM951 M.2 drive I added the following VIB
Add-EsxSoftwareDepot sata-xahci-1.32-1-offline_bundle.zip
For my Adaptec 6405e I added the following VIB (but this did not work even though the Acceptance Level was PartnerSupported)
Add-EsxSoftwareDepot c:\vmware\aacraid-offline_bundle.zip
And the ESXi was Get-EsxSoftwarePackage -name esx-base
esx-base 6.0.0-0.0.2494585
The package "sata-xahci-1.32-1-offline_bundle.zip" was CommunitySupported but everything else I had was PartnerSupported, so I changed the level of my new image to CommunitySupported
PowerCLI C:\vmware> Set-EsxImageProfile -Name ESXi6-M2 -AcceptanceLevel CommunitySupported
Then I could add it
PowerCLI C:\vmware> Add-EsxSoftwarePackage -ImageProfile ESXi6-M2 -SoftwarePackage sata-xahci
And make my ISO
PowerCLI C:\vmware> Export-EsxImageProfile -ImageProfile ESXi6-M2 -ExportToISO -filepath c:\vmware\ESXi6-M2.iso
And it ...sorta worked!!!! my ISO booted and the installer saw my Samsung SM951 M.2 drive... and installed ESXi
However, strangely, the single drive off the Adaptec drive was NOT seen by the installer, even though the BIOS sees it and I was able to format the single drive via the card's utility...
And here is the cincher: while I was able to install ESXi onto my M.2 drive, it would not boot, and in fact, the board would not allow me to select it as a boot device.
YUK... ok so what happened? #1 I dont know what the deal with the Adaptec card and its drivers are!
Howver, I have found out that my Samsung SM951 M.2 drive is an AHCI type... instead of an NVMe. I bought it from Newegg under N82E16820147431 but newegg did not list the type, and moreover, did not list the full part number so there was no way I could tell
I opened up my server and transcribed the full part number: MZHPV128HDGM-0000 or MZ-HPV1280
So the way to tell is the 3rd digit:
MZVPV = NVMe
MZHPV = AHCI
AsRock / AsRack was really awesome with their help regarding my ASRock C226M WS Micro ATX Server Motherboard LGA 1150 DDR3 1600/1333 board. So it turns out in Tawain, there is great availability for the NVMe M.2 and thus this is what the BIOS team tested against. But there is hope. I slightly different current board by ASRock which also has a M.2 slot had the exact same problem: drive visible and listed in bios but not selectable as a boot device when AHCI whereas selectable if NVMe
They think that they can probably cook up a BIOS update for me that will address the issue of AHCI M.2 on the C226M chipset
I want to say that this link totally helped me complete the image:
...Still have no idea what is the deal with the adaptec aacraid-offline_bundle.zip drivers working with the Adaptec 6405e!!