Your Boondock Echo has a built-in USB→UART interface on the port in the middle of the device (closest to the SD card)
The left side of the boondock echo has, from left to right, openings for an SD card, a connection for a micro USB→UART cable, and a power-only micro-USB port.
Note: If you have not already done so, please download and then install the CP2102 virtual com port drivers for your computer.
Plug a micro-USB cable into the Boondock Echo and into your computer. You can use the WebTools interface or your favorite terminal program. (If you use your own program, connect to the correct com port at 115200 baud.)
You can access the list of commands by typing "help ?"
Set the Boondock Echo to the offline mode by typing "offline 1"