I have posted my method to connect multiple Argons and Xenons at
a video is coming. This only works for Mac and Linux users but I will be looking into a cloud solution. To get devices back to normal remember to download the latest release for DFU flashing.
presently at https://github.com/particle-iot/device-os/releases/download/v1.4.1-rc.1/particle_device-os@1.4.1-rc.1.zip
Then to install in DFU mode
particle flash --usb argon-system-part1@1.4.1-rc.1.bin