If you own the lerdge USB/Wifi printing module, you've probably looked at that 8 pin header and thought "It would be nice to do serial printing." And it probably would. However, in the lerdge store's description, they basically say other ESP8266-01 modules don't work.

It's sort of a lie, sort of not. Lerdge does not release their firmware (though anyone with a module could dump it), and they don't document how the connection works. But that doesn't mean much to me, so I ordered a $2 ESP8266-01 from China, and when it arrived, I flashed ESP-LINk on it and plugged it into the lerdge. After adjusting for my hideously slow baud rate (again, probably a clock problem)

I got the following output:

So...can we enable standard Wifi Serial printing? Yes.

Is it easy/Working? Not yet. But it's not far off. 

There's no custom code other than my marlin build at work here, so it's almost certain we can use the ESP8266 wifi printing code directly on the board once we get it running. I'll be checking the oscillator config soon to see why we're having problems, and I'm hoping that's directly related to why USB and SDIO don't work yet.