The 1st release of AudioMoth Flash app has an issue where it can fail to fully load the new firmware.
So the "old" way is via a stand alone utility called "flash"
Now this is for Windows 10 because that is what I use.....
Download flash and the firmware bin file and put them in the same directory. I use the root of my user files c:\Users\david
Start the windows CMD app and plug in your audiomoth with the switch set to USB/OFF
To list the port the AudioMoth is attached to type:
flash
<the reply should be something like below>
COM4
To access the serial number of the AudioMoth device:
flash -i COM4
<the reply should be something like below>
Serial Number: 24410E05588EF20C
To upload the firmware binary file to the device.
flash -u COM4 AudioMoth1.0.0.bin
<the reply should be something like below>
Programmed: 41412 bytes
Flash CRC: 4393
To check the CRC of the current flash.
flash -c COM4
<the reply should be something like below>
Flash CRC: 4393