Adafruit feather M0 wifi firmware update
USE AT YOUR OWN RISK
Here's what I did... (maybe some steps not necessary, but this worked for me)

1) First run the "CheckWifi101FirmwareVersion" found in the Arduino WiFi 101 library.


NOTE: You need to add in the WiFi.setPins(8,7,4,2); after void setup() {
If it's backlevel (before 19.4.4), then


2) Download the Adafruit WiFi101 Updater on github (
   https://github.com/adafruit/WiFi101-FirmwareUpdater/archive/master.zip
   )

3) Install the "FirmwareUpdater" from the Arduino WiFi 101 Library


Add in the recommended changes (even if it's the defaults)

#define WINC_CS 8
#define WINC_IRQ 7
#define WINC_RST 4
#define WINC_EN 2 


and the usual WiFi.setPins(8,7,4,2) after void setup() {


4) Copy the firmware you wish to flash to same directory as "winc1500-uploader.exe"

5) Run the command: 


  winc1500-uploader.exe --port [YourComPort] --firmware [YourFirmwareFileName].bin


So for example I did:


  winc1500-uploader.exe --port COM9 --firmware m2m_aio_2b0.bin