Flash system FW from 0.7.0-rc.3 to 0.6.2 problem / Safemode

I flashed my Photon with user code targeting 0.7.0-rc.3, and due to issues with the app-hash not working properly in some cases (Weird flash compile Issues, not seeing app-hash event?), I am trying to roll the Photon back to 0.6.2

I used the following commands (i read somewhere to do it in reverse order, but I also tried it part1 then part2):
dfu-util -d 2b04:d006 -a 0 -s 0x8060000 -D system-part2-0.6.2-photon.bin
dfu-util -d 2b04:d006 -a 0 -s 0x8020000:leave -D system-part1-0.6.2-photon.bin

The update took and it reboots… but it just boots up in to safe-mode.

I can verify the current version is now 0.6.2, but all it does is boot to safe-mode. I tried flashing my user code to it again targeting 0.6.2 now, and it doesn’t take… It just reboots back into safe-mode again.

I am stuck- any suggestions?

(ps): I asssumed the dfu-util 0x8020000 is for part1 and 0x8060000 is for part2 - I couldn’t find any good documentation explaining these parameters. So maybe those are backwards? Not sure. Bottom line, I need to revert back to 0.6.2 and its stuck in safemode.

Have you read this

You can use

particle flash --usb <binary>

for the system parts and for the bootloader

particle flash --serial <bootloader.bin>

I have not read that. This needs to be better documented somewhere. The only articles I read said nothing about the bootloader.

So I need to do 3 parts (system-part2 -> bootloader (v0.6.2) -> system-part1), and reboot it after each part before proceeding to flash the next part?

What is the difference between “particle flash” and dfu-util?

particle flash --usb checks the compatibility of the binary and chooses the right location from the binary itself.
So less risk of using wrong binaries or wrong addresses.

Can you confirm my question above?

Also. I tried your suggestion, and got an error:

particle flash --serial system-part2-0.6.2-photon.bin
! PROTIP: Hold the SETUP button on your device until it blinks blue!
? Press ENTER when your device is blinking BLUE
sending file: system-part2-0.6.2-photon.bin

! serial:
Error writing firmware…Transfer cancelled

If I try it in USB/Dfu mode, system part 2 takes, but bootloader doesn’t:

particle flash --usb system-part2-0.6.2-photon.bin
Found DFU device 2b04:d006
spawning dfu-util -d 2b04:d006 -a 0 -i 0 -s 0x08060000 -D system-part2-0.6.2-photon.bin
dfu-util 0.8
Opening DFU capable USB device…
ID 2b04:d006
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 = 0x08060000, size = 213760
Download [=========================] 100% 213760 bytes
Download done.
File downloaded successfully
Invalid DFU suffix signature
A valid DFU suffix will be required in a future dfu-util release!!!

Flash success!

particle flash --usb bootloader-0.6.2-photon.bin
Found DFU device 2b04:d006

Error writing firmware…unknown module function 2, use --force to override

Try to do the flash --serial when it’s in safe mode or flash tinker to it. I found that the user application may affect the --serial transfer.

I said --usb for the system parts and --serial for the bootloader.
--usb requires DFU Mode (blinking yellow)
--serial requires Listening Mode (blinking blue)

Thanks, I will try that the bootloeader with --serial. However, that is NOT what you said. (Quote above). So are you still saying I need to do system part 2 with --usb (reset), then bootloader with --serial (reset), then system part 1 with --usb (reset)? You never confirmed the order.

Hmm, I thought I said this:

If you read the quote as one sentence, you may find the bit before the “and” refers to the top command and after the “and” to the bottom command.

You’re right, I misread it because of where the “and” was. I can see how one can read that two different ways.

What about the order? Is this right?

Flash system part 2 with --usb (reset)
then bootloader with --serial (reset),
then system part 1 with --usb (reset)

Yes, this is how I’d do it with enterint the respective mode for each step: DFU -> Listening -> DFU

And finally I’d run

particle flash --usb tinker

in DFU Mode to get everything wrapped up.