Need EE help! What "ssd" interface is this? picture...

Yoga 2 11 Haswell i5 ... the part you are looking at officially does not exist, apparently. not msata [that I know of] nor m.2 [ditto] certainly not mini SATA... but it is definitely some sort of ssd interface - a "slot" in the tray [holder really] for typical SSD dimensions up to 80mm long.
officially this unit per serial shipped with, a specific samsung M.2 drive that has a totally different connector - so it did not happen. maybe built that way, then "unbuilt" and something else added. its no hack job - very clean, undisturbed except 'drive remove for security reasons'

 

It's SATA at least (label) and certainly looks every bit M.2 B key ... could check part nr. of the connector's pcb to make certain. The Samsung drive may have been SFF-8784 type, that would neatly match the cable going to the pcb, making the blue pcb an SFF-8784 -> M.2 adapter. Tried an M.2 yet?

 

I have not ordered a drive yet. had I done so, it would have surely been wrong!
Yes I tried diligently to search the vendor's pcb but pulled a zero - same with the maker.
details:
vendor: PALMONN [the M may be a H].. Rev. 1.0 AIUU3 NS-A341
there are no other significant markings on it except the port for the presumed "vienna" drive cable connecting to mboard, marked 'JSATA' at both the ssd connector and mboard.
I doubt there is more than one interface on the series. the diff is in what that little cable plugs into @ the bay

 

Indeed, there's only one interface; SATA, whichever connector it uses. The service manual only lists two types of slim drive (all hdd) with two types of cable/connector; one SFF-8784 and the other regular SATA. You probably haven't received that last cable as an extra, but if you'd get one then it's possible to use a 7mm SATA ssd. Would have to remove caddy and, perhaps, use a bit of padding (since you miss the regular hdd caddy). Do think that what you have really is an M.2 adapter (+ removable black plastic caddy), even though the service manual doesn't list those yet. Either way; a slim 2.5" ssd would fit too, might be a bit cheaper and will run cooler to boot.

 

I should create a new post just on the drive itself. it is painfully daunting to even find one or two
'single notch' SATA SSD's, for certafin. I have sent many messages to vendors, suppliers, and users [ie. amazon reviewers] asking questions about the actual drive received/installed vs what they thought they were getting.... sheesh what a minefield. MANY mistake PCIe because the physical interface appears to be same . Many sellers show 'stock photo' of a single notch M-Key type but upon asking for verification it appears to be phiction... its really a full B+M iteration. the only ones I see are a pair of samsungs that SEEM to be workable and are exquisitely expensive.
I am not certain at all that the drive in some of the macbooks is the same spec/pinout/firmware necessary for my interface, but there is the same high level of angst and need for some of those models....
lack of standard acceptance... lack of standard terminology.

i've ordered a regular sata interface for it...