I have noticed with alot of the Newer MSI Motherboards SMOS just really doesn't work with them. Here is an example of several scenarios in which nothing has solved the issue.

MSI Board H270a-PRO

SMOS on usb 3.0 16gb flash drive.

Will boot up without 4g encoding enabled. ONLY runs max of 4 cards though.

With 4g encoding enabled will not boot, gets stuck on a screen with some really funky looking colors.

I have tried with the 3.0 in the 2.0 slots, 3.0 slots and I have even tried using an ssd. All the same result will not boot with 4g encoding enabled.

What does work, a Ethos usb or ssd. 4g encoding enabled and 7 card cards run just fine like a champ.

My thought is that these MSI boards need to have the OS be UEFI in order to utilize 4g encoding. That's the only difference I can see between ETHOS and SMOS is that the ETHOS drive (usb or ssd) is UEFI and not Legacy. 

Has anyone else had similar issues?