Bootloader version mismatch after upgrading Xenon from 0.9.0 to 1.2.1

Connectivity BLE // NFC
2

Updating from a firmware prior to 1.2.1 (IIRC) the bootloader cannot be flashed via DFU Mode (using --usb).
You’d need to put the device into Listening Mode and use particle flash --serial xenon-bootloade@1.2.1.bin