Ok, I'm back to it again, even though I'm still missing my mSATA adapters. I decided to use a spindle for the VM Datastore. The current plan is that I'll add the SSD later when I receive my adapters and then just move them over and remove the spindle.
This isn't an update per se, more of a sigh of relief really and this maybe help someone else out, if they get in a jam like I did.
I got everything pretty much together and settled down to get some installs and config done, but immediately hit a bump in the road. I discovered that for some reason I could no longer boot an x64 VM. What was really strange was that ESXi complained that VT-x was not enabled. I checked the bios, it said supported, VT-d was enabled etc and no other obvious signs of issue. I must have checked it a dozen times, but was missing something.
Ok, so what appears to have happened, although I cannot explain exactly how it happened, the bios has become corrupted and switched off VT-x. So off I go to find an updated bios, thinking easy peasy fix. It turns out after a little digging that my mainboard is a B400 manufactured by Inventec. I know, obscure huh? They are not exactly unknown to me as it turns out, and are a massive asian ODM company that design everything from kettles to satelites. Obtaining a bios update from them though is simply not on the cards. Nor for that matter, is there any chance of tracking down the actual asian board manufacturer. These guys like to remain anonymous, leaving little or no clues on the board or in the documentation. So I then turned my attention to AMI. It's their APTIO 4 uefi firmware and bios that is being used, as is often the case with older small server type boards. Much searching later and still no luck. I can find a gazillion different boards, everything from desktops to miniITX all using the same general bios version, but each having different modules and configurations tailored specifically for each board. Mine is obviously not amongst them. My heart sank, I've been here before with other non-branded boards with varying degrees of luck/ success. I decided that I'm not taking this lying down. I feel that it's a good mainboard in most other respects, but I knew that this may be a very long road to travel for a fix.
Getting my hands dirty modifying a uefi bios is not for the faint of heart. It could easily end in complete misery with an unbootable board, but undeterred I went on the hunt for some AMI software tools never the less. The tools I went looking for specifically were AMI's bios flash utility, AFUWin and their MMTool for APTIO version 4x. I also came across a nice little bios tool called UEFITool along the way, which is really useful for pulling out and extracting bios setup menus and the like, if that floats your boat. First things first. I ran the AMI flash util and save a copy of the original bios, just in case, then make 2 more copies of it so it's not accidentally overwritten and there is some way back should it all go sideways.
As it turned out, using the tools to dump the bios setup menu, I discover that there is a whole load of things disabled that I was not aware of to begin with, not just VT-x. Most of which I really don't need to bother with, but there were a couple of items that would be handy to have back again. I was really too tired last night to start back tracking the code looking for entry points, so went looking for an easier vector to take. This was when I remembered about AMIBCP for version 4x. After some digging on the web, I managed to get my hands on it and after opening the saved bios with it, I was able to look through the various setup screen menu items and re-enable them to be visible and modifiable. Once I finished tweaking things, I saved the bios file with a new name, and using the flash util, I "upgraded" my own bios. I was then able to go into it at boot and switch on VT-x again and a couple of other little tweaks too. The outcome is that ESXi now installs without complaint and runs x64 VM's again without issue. Success, and surprisingly, without the pain I was expecting.
I count myself very, very lucky here. I could have been digging into code for a while to fix this, but as it turned out, the menu items had simply dissappeared and been disabled. In retrospect, I can only assume that the bios was originally updated, after all it was working to begin with, and at some point when I have been in the bios setup doing something else, I have somehow triggered the bios recovery mechanism which overwrote the updated bios and disabled things. The most likely cause of this I can think of would be a vanilla AMI bios copy in the recovery blocks and the one that the board manufacturer had been playing with to get things working in the bios blocks. They must have not updated the recovery blocks when they were done tweaking
Anyway, a huge sigh of relief for me and I can now get my installs done when I get some more time to play with it. Hopefully this will help anyone else that has a similar issue.