Electron - can not load firmware

I have an electron that appears to be stuck in DFU mode - yellow flashing. When I remove all power and reapply power - USB power and/or USB + battery - it come up in DFU mode. Pressing the reset and / or mode button have no effect - always returns to DFU mode.

particle flash --usb tinker -v
particle update -v
particle doctor
all give the same errors message
Error writing firmware: dfu-util: Invalid DFU suffix signature
dfu-util: A valid DFU suffix will be required in a future dfu-util release!!!
dfu-util: Error during special command “ERASE_PAGE” get_status

Since I can not get the device in “listen” mode - blue flashing, I can not attempt to reload the boat loader. I have been through the community suggestions and attempted all suggestions but always end up in the same place.

macOS and the latest versions on CLI and workbench.

Any suggestions?

If you had a fairly recent device OS on the device before you got these troubles chances are that you can also use particle flash --usb to update the bootloader.

If that doesn’t work you may want to file a support ticket at support.particle.io

Thank you - I was attempting to go from 0.6.4 to 1.5.2. Worked with issue with two units and be sideways with the third.