Bricked my D2 Charlie while trying to flash the Fenix 5 X firmware. Can I force firmware on it with a jtag flasher or sth the like?

I found a  firmware in the internet called "Convert_D2_Charlie_to_Fenix_5X" consisting of 2 files:

D2Charlie_550_to_fenix5X_1300.gcd

GUP2605.GCD

I renamed the "D2Charlie_550_to_fenix5X_1300.gcd"  file to gupdate.gcd and copied it into the Garmin folder on the watch and I copied the GUP2605.GCD into the Garmin\REMOTESW folder.

Then I rebootet the watch, and it asked me if I wanted to perform the firmware update. I accepted it, and since then, the watch is bricked, means it keeps cycling the Garmin logo on and off and cannot come out of that stage. I tried the soft and hardreset plenty of times, but it wont change anything.

When I connect the watch to the computer, it is not recognized as a drive anymore, so no way to manipulate the files.

One thing though, when I connect the watch to the computer and switch it on while keeping the start button continuously pressed, then it shows up on the computer as a "Garmin USB GPS" device. But only while I hold the start button.

Thats it.

Anyone have an idea how to get the files accessed on the watch, to delete the faulty firmware files?

I´m afraid that it will be very expensive to get the watch exchanged by Garmin since it is such an expensive watch and it is far out of warranty... :-(

  • If hrd reset neither cable to computer work it looks difficult. Did you try this?

    Hard reset / factory reset:
    Turn OFF the watch
    Press and HOLD LAP button
    Power on (still holding the LAP button)
    You will get the menu “Clean user data: Yes/No?” release LAP button
    yes

  • Hi, yes I tried that as well. The watch just keeps blinking the Garmin Symbol, even if I hold the Lap Button more than one minute after starting the watch from the OFF mode.

    The only things that work with buttons that I know off right now, are:

    -switching the watch on and off
    -holding the lap and start button until it beeps, and then letting the start button go on the first beep, and the lap button on the second beep
    -keeping the start button pressed, and while holding the button, the watch shows up on the computer as Garmin USB GPS

  • Hmm, sad story. If you would be able to get to situation that you see the watch as a disk (even with keeping held button) and got a chance to copy in some version of D2 firmware, it may help to start the watch. That would be the last chance I see. If not, try to contact Garmin support, maybe they will have some piece of advice over the phone. If not, then you will have to send the watch to service, it will be expensive but worth anyway, I think.

  • I think the firmware has damaged the file system on the device. So Windows don't recognize it.

    Maybe there is a little chance with Linux, which can handle raw storage. But you need the original D2 firmware, and if you don't have a D2 firmware backup this also doesn't help you.

    As  already said, the only promising way is to contact Garmin support.

  • Yes it is indeed very sad. The Garmin support can´t help as they said, the watch is not reachable on the file system.

    On top of that, they don´t do repairs, they only do exchanges from a refurbished watch pool for a standard fee which roughly comes down to one third of the price for a new watch. BUT, the crazy part is, they said the D2 Charlie is not available anymore in the refurbished pool since it is discontinued. I asked Garmin if this means I can basically throw away the watch, and they confirmed this.

    I can now throw away my 1000€ watch, because of an unrepairable software error, even though the hardware is working perfectly fine...

    That was Garmin Germany where I bought it...

  • I just saw your reply, I have copied the complete file system from the Garmin watch before to my computer. Around 8GB of data. Would this qualify as a firmware backup, that I could push to the device through linux?

  • in this case it still worth to continue trying. Try with Linux computer, as Subra proposed, seems good idea. There are bootable USB sticks options with i.e. Ubuntu. I think there are 2 ways: one would be to copy the backup you have, the other would be to put the latest firmware of D2 - if you ask in D2 forum, many folks have it. I also have for 5x but that one you dont want :).

  • It's only a thought from me, and you've no other chance to revive your watch. Maybe the Linux command dd can help to recover the file system, but there is no guarantee. So you've the choice to give it a try or throw away the watch in the bin.

  • Hehe thank you guys. Obviously I will give it a try and will spend as many hours as needed. The Charlie is still very good if it works, with the features for flying :-)

  • I just realize it will probably not work also on linux. The slowly on and off blinking of the garmin logo on my watch means, that the watch does not boot. It is stuck in an early boot stage. So it will most likely not be available to give access to it´s file system to any computer, no matter if linux or windows. If the file system was accessible, it would also indicate this on windows as a removable disk.

    In electronics for these cases normally there are flashing tools like jtag, where the device does not really need an operating system to come on, but the jtag controller for example can talk to the disk bit by bit to push data onto it.

    If Garmin doesn´t have this, a watch becomes unusable if you can´t access it´s file system.

    Correct me if I´m wrong.

    I´ll check on linux though, if I am able to mount any kind of disk when the watch is plugged in....