All 3D printers have an embedded USB-TTL converter, such as FT232, CP2102, CH340. Now you want to control your printer over WiFi. Great, you can now plug in 3DESP and communicate over telnet. You might consider
1. Hacking the board and add an ESP8266 module to any one of TXRX. But chances are that you use an OEM machine and you don’t want to void warranty.
2. Buying another 32-bit board which already has a socket of ESP-8266. Yet they are too expensive and you dont’ want to set everything again.
But I won’t. All you need to configure 3DESP is to compile and upload different versions according to your USB-TTL converter. After all, we can’t compile all drivers in one chip, right?