Attempting to flash a bootloader over USB should report that it is not supported

[zfields]

It's my understanding it is impossible for the bootloader to be flashed over USB.

I get an error if I don't use the --force override.

However, if I do --force the CLI reports success. The device slow blinks yellow, then reboots and reconnects (breathing cyan).

zak@zPro:~/binary_output_interface/1.0.1/photon$ particle flash --usb ./release/photon-bootloader@1.0.1.bin 
Error writing firmware: unknown module function 2, use --force to override
zak@zPro:~/binary_output_interface/1.0.1/photon$ particle flash --usb ./release/photon-bootloader@1.0.1.bin --force

Flash success!

[monkbroc]

Do you know what actually happens when that second command runs? You can use --verbose to get more output from the DFU flash.

What would you expect to happen when you force flash an invalid binary to the device?

[zfields]

Not this...

Flash success!

At least not in this circumstance, because nothing actually happened.

[monkbroc]

The dfu-util flash command does complete successfully so the CLI reports Flash success!

$ particle flash --verbose --usb --force bootloader-1.0.1-electron.bin
dfu-util 0.9

Copyright 2005-2009 Weston Schmidt, Harald Welte and OpenMoko Inc.
Copyright 2010-2016 Tormod Volden and Stefan Schmidt
This program is Free Software and has ABSOLUTELY NO WARRANTY
Please report bugs to http://sourceforge.net/p/dfu-util/tickets/

dfu-util: Invalid DFU suffix signature
dfu-util: A valid DFU suffix will be required in a future dfu-util release!!!
Opening DFU capable USB device...
ID 2b04:d00a
Run-time device DFU version 011a
Claiming USB DFU Interface...
Setting Alternate Setting #0 ...
Determining device status: state = dfuIDLE, status = 0
dfuIDLE, continuing
DFU mode device DFU version 011a
Device returned transfer size 4096
DfuSe interface name: "Internal Flash   "
Downloading to address = 0x08080000, size = 16344
Download	[=========================] 100%        16344 bytes
Download done.
File downloaded successfully

Flash success!

Let's rephrase the issue as "attempting to flash a bootloader over USB should report that it is not supported"

[partictim]

Interestingly, I just used --force attempting to --usb update the bootloader on a B402, and have corrupted the bootloader such that the device now won't boot the appFW. Now hunting for an adapter cable to connect my ST-Link.