It is not possible. In addition to the missing socket, there are other components missing, some are under the shield.
Care to elaborate? Not much should be required, so this is a bit surprising, unless it's an intentional disabling.
That said, USB-based storage could be another option - but it should be kept in mind that neither is robust in the face of unexpected shutdowns/reboots - one of the real strengths of these platforms over the computationally far more powerful and hardly more expensive raspberry pi, is that they don't depend on a fragile SD card. If you could boot a pi W from an SPI flash, it's questionable if there would be a market for MT7688 systems at all.
@Jeff-Seese Thanks Jeff, I was not aware such a thing existed ! This may be of use in another product where the SD card needs to be accessible by the end user, to change the content as and when required.
But still, if I only could have the connection details ....
0.1.9 b149 is pretty old. I am one behind at b156, but it has been stable with some bugs worked out. Maybe download and install it, as a number of other packages have been upgraded since the release of b149. Or even to b157. Just a thought.