Overview
The below describes an alternative method of connecting an ESP8266 to the Fly-407ZG.
There are two different methods. One frees up the EXP2 header only and the other frees up both the EXP1 and EXP2 headers.
This alternative modification provides 3 advantages.
* SPI controlled drivers (TMC5160) can be used
* EXP2 (method 1) or both EXP1 and EXP2 (method 2) are freed up for other uses
* Both RRF updating of the ESP8266 and serial displays can be used at the same time
This will involve soldering some cables to the board.
BOM
- 1 x ESP8266 adapter (any of the 3 types will be suitable)
- Some cable
Connecting the Adapter
This example uses the Fly WiFi Adapter but the instructions are applicable to all 3 types.
Method 1
Cables to solder to the Fly-407ZG
7 cables are to be soldered to the board. 5 of these are on the onboard ESP pads and the other 2 are on the EXP1 connectors.
Connect the 5 cables to the Fly-407ZG as shown below

Connect the 2 cables to the Fly-407ZG as shown below

Cables to solder to the Adapter
The 7 cables soldered to the Fly-407ZG then need to be attached to the adapter.
2 of the 5 cables should be attached as shown below. The RX cable from the Fly-407ZG should be connected to the TX pad on the adapter and the TX cable from the Fly-407ZG should be connected to the RX pad on the adapter.

The remainder of the cables are to be connected to the adapter as shown below.

Other Connections
Connect a cable between EXP1 on the Fly-407ZG and the adapter.
Board.txt Changes
The following changes should be made to the board.txt file
//ESP8266 Settings
8266wifi.espDataReadyPin = PE_15;
8266wifi.TfrReadyPin = PB_10;
8266wifi.espResetPin = PE_14;
8266wifi.csPin = PE_12;
SPI2.pins = {PB_3,PB_4,PB_5}
8266wifi.spiChannel = 2
8266wifi.serialRxTxPins = { PG_9, PG_14 } ;
Method 2
Cables to solder to the Fly-407ZG
11 cables are to be soldered to the board. 6 of these are on the onboard ESP pads, 3 to the eeprom and MAX6675 connections and 2 to EXP1.
Connect the 6 cables to the Fly-407ZG as shown below

Connect the 3 cables to the Fly-407ZG as shown below

Connect the 2 cables to the Fly-407ZG as shown below

Cables to solder to the Adapter
The 11 cables soldered to the Fly-407ZG then need to be attached to the adapter.
2 of the 11 cables should be attached as shown below. The RX cable from the Fly-407ZG should be connected to the TX pad on the adapter and the TX cable from the Fly-407ZG should be connected to the RX pad on the adapter.

The remainder of the cables are to be connected to the adapter as shown below.

Board.txt Changes
The following changes should be made to the board.txt file
//ESP8266 Settings
SPI2.pins={ PB_3, PB_4, PB_5 }
8266wifi.espDataReadyPin = PB_7
8266wifi.lpcTfrReadyPin = PB_6
8266wifi.espResetPin = PA_4
8266wifi.csPin = PG_15
8266wifi.spiChannel=2
serial.aux.rxTxPins = { PA_10, PA_9 }
8266wifi.serialRxTxPins = { PG_9, PG_14 }