Necro'ing this topic but I thought I'd post the solution.

I was stuffing around with ILI9341 displays on an Arduino Pro Mini but couldn't really get them to work properly at 115,200 baud, even if I increased the serial buffer to 1k.

Instead, I got a NodeMCU v1.1, and installed the excellent ESP-LINK firmware on it.

I now have a serial console via Wifi to the Mysensors controller with close to zero effort on my part.

The only change I needed to make (on the Sensebender Ethernet Gateway) was the following line to direct the output to the serial port in the MYSX connector:

#define MY_SERIALDEVICE Serial1

I had the same problem.

For some reason I'd connected NRF_CE to Pin D4 instead of D9.

Simply putting #define MY_RF24_CE_PIN 4 made all the problems go away but I lost a couple of days figuring that out. I assumed the radio was connected fine as it was talking to the gateway, it would just not ACK messages.

The gateway would show:

7222879 !TSF:MSG:SEND,0-0-6-6,s=255,c=3,t=8,pt=1,l=1,sg=0,ft=0,st=NACK:0

(Running 2.2.0.rc2)