Convert fenix 5S/5/5X Plus to D2 Delta S/Delta/Delta PX

@mbirth,
After some experimenting I managed to upgrade to v4.0 (it took using the new GCD file and manually dragging it to Web Updater).

Tried your suggested procedure (Holding top right button pressed; and without releasing it turning the device on). The watch proceeds to boot even before I release the D2 (top right) button.
Doing so after copying the patched 5x Plus gupdate.gcd file made no difference.
The watch did recognize the patched firmware ("v310 Available"). Choosing "Install Now" the watch proceeds to install the update, but still boots as D2 v4.0. I tried several times - including while having the top right button pressed during the update and through the boot process - with no luck.

Thanks again for your continuous support!

Edit:
@mbirth,
Posted my previous reply before seeing your latest one.
I downloaded a current 5Plus gcd file, and dragged it to the Web Updater desktop Icon. Pressing the top right watch button (while watch is off), and connecting to the sync cable - the watch proceeds directly to boot (not pausing a the blue triangle) - not sure I'm correctly following your instructions...

Quote:

---

Originally Posted by DPIN [Only registered and activated users can see links. Click Here To Register...]

the watch proceeds directly to boot (not pausing a the blue triangle) - not sure I'm correctly following your instructions...

---

You're doing it right, but the watch directly booting suggests they still didn't implement this feature in the D2 bootloader or there's a different button (or button combination) to hold. On my F5P when holding the top right button while powering on the watch (or plugging into USB - which powers on the watch), it stays at the blue triangle as long as I keep holding the button. And during that time, I'm seemingly able to flash whatever firmware I want - the watch accepts them all.

A couple of years ago, I did the conversion through your method and it has worked great. I love the watch so much that I decided to buy a used one on Ebay as a backup, in case I lose the one I have. Crazy I know, but the watch does everything for me, from aviaton, sports, etc... and knowing that the D2 will be discontinued, then it makes sense.
I found your old post on how to proceed, so hopefully I can figure it out. The only problem I have, I cannot find the D2 firmware. Do you happen to have it ? Where do I find it ? I assume that I could flash to an old one and then upgrade later.
Thanks for your help.

I've collected all necessary files here:

[Only registered and activated users can see links. Click Here To Register...]

There are also _Backdate firmwares in case you're already on a newer firmware than needed for conversion.

Thank you so much !! Any way to donate for your work ?

If I understand correctly I should be able to flash a Fenix 5X Plus to a D2 PX by downloading the current D2 PX firmware (e.g. D2DeltaPX_610.gcd) and flashing it via Garmin's web updater. Years have past, is there reason to believe Garmin has changed anything in the Fenix 5 firmware that prevents flashing D2 firmware?

The first post suggests conversion to rgn is required. When I use the rgnTool to write a rgn, the tool complains boot.bin should be in section 1...hope you know what you are doing. Should I assume this message can be ignored?

For reference I own an older D2 without PO2 sensor and it would be useful to get a backup watch, as well as obtain the capability to measure PO2 at altitude.

Thank you.

Not sure I understand what you are asking about the PO2 sensor. If you don't have the sensor on your watch, you can't flash it to have that.
I did the flashing a couple of years ago and it's worked great. Not a problem. I was wondering the same if there would be anything that they might have changed. My understanding (not an expert at this), you just flash whatever firmware you want. You can flash an old one and the watch will update to the latest one. In other words, Garmin doesn't know if you did the flashing or not.

Quote:

---

Originally Posted by Serhito [Only registered and activated users can see links. Click Here To Register...]

Thank you so much !! Any way to donate for your work ?

---

I'm happy if you're happy. :) No donation necessary.

Quote:

---

Originally Posted by vscvsc [Only registered and activated users can see links. Click Here To Register...]

If I understand correctly I should be able to flash a Fenix 5X Plus to a D2 PX by downloading the current D2 PX firmware (e.g. D2DeltaPX_610.gcd) and flashing it via Garmin's web updater. Years have past, is there reason to believe Garmin has changed anything in the Fenix 5 firmware that prevents flashing D2 firmware?

---

That's not quite right. Garmin firmwares check whether the firmware was meant for that device by verifying the hw_id (device/model number) and some flags in the firmware files. If they don't match, the firmware isn't installed - even if the hardware is exactly the same. That's why I've modified the firmware files on the MEGA share so e.g. the hw_id and flags of the D2 Delta firmware match those of the Fenix 5 Plus.

Quote:

---

Originally Posted by vscvsc [Only registered and activated users can see links. Click Here To Register...]

The first post suggests conversion to rgn is required. When I use the rgnTool to write a rgn, the tool complains boot.bin should be in section 1...hope you know what you are doing. Should I assume this message can be ignored?

---

Please don't use that method anymore. It worked for converting a Fenix 5 Plus to a D2 Delta, but was a one-way thing as e.g. the D2 Delta bootloader doesn't have the Preboot mode needed to force-flash the RGN. The method using the modified firmware update files is much safer and works in both directions.

And as Serhito pointed out already, you can't add hardware features this way. If there's no SpO2 sensor (i.e. a red led) on your watch, a firmware change can't add it. Also, flashing e.g. the D2 Delta firmware onto a D2 Charlie won't work either as those have different hardware specs and you'll most probably end up with an expensive paperweight.

My posting was confusing. I understand flashing code doesn't make up for hardware that is simply missing.

In short I already own a D2 Delta w/o the PO2 sensor. It's a great watch but now I'm flying at higher altitudes where supplemental O2 is required. An option is to buy a Fenix 5X Plus and flash the D2 PX firmware onto that hardware which has the PO2 sensor. But a lot of time has passed from when you documented successfully flashing a Fenix with the D2 firmware. Thus I'm concerned what Garmin is shipping now still permits flashing over the Fenix code.

Via searching with Google I have done my best to read everything that came up from the search, but clearly using modified firmware didn't pop up on my search. But now that I'm looking at the MEGA files you created modified firmware for the Fenix 5 plus, not the 5X plus.

I found your Python code. I believe I'm using it correctly and I'm able to change the HW_ID for the current D2 delta firmware to the Fenix (e.g. 3111 or 0xc27). That said what flags need to be changed? Also is the first second the boot loader, where you are using the Fenix boot loader with the "payload" from the D2, when building the flashable D2 file?

Note I download two firmware files from Garmin, one for the D2 Delta and the other for the D2 Delta PX. Comparing the files, they are identical byte-for-byte. Interesting....

Quote:

---

Originally Posted by vscvsc [Only registered and activated users can see links. Click Here To Register...]

Thus I'm concerned what Garmin is shipping now still permits flashing over the Fenix code.

---

AFAIK those watches are cross-flashable regardless of their firmware version. There are downgrade firmwares to downgrade to an older version from which you can cross-flash a Fenix Plus to a D2 Delta.

Quote:

---

Originally Posted by vscvsc [Only registered and activated users can see links. Click Here To Register...]

But now that I'm looking at the MEGA files you created modified firmware for the Fenix 5 plus, not the 5X plus.

---

All Fenix 5 Plus variants and - as you already found out - all D2 Delta variants have the same firmware. The Fenix 5 Plus firmware runs under hw_id 0x0b54 (fenix 5S Plus) and the D2 Delta range has hw_id 0x0c7c (D2 Delta S). So the files in the MEGA folder work for all variants.

Quote:

---

Originally Posted by vscvsc [Only registered and activated users can see links. Click Here To Register...]

I found your Python code. I believe I'm using it correctly and I'm able to change the HW_ID for the current D2 delta firmware to the Fenix (e.g. 3111 or 0xc27). That said what flags need to be changed? Also is the first second the boot loader, where you are using the Fenix boot loader with the "payload" from the D2, when building the flashable D2 file?

---

In case of the watches, there are the fields 1014 and 1015. Those have to match for the watch to accept the firmware file. First binary in the GCD file is the bootloader, the second one the actual firmware. You must always flash both (which means modifying the flags twice in the .rcp file) when cross-grading as a firmware upgrade has 2 stages:

1. The main OS verifies whether the firmware file matches the current running one (hw_id, 1014, 1015, newer version) and if it does, copies the GCD to some staging area.
2. The watch reboots and the bootloader now does the same verification again. If it doesn't match, the update is discarded.

Now imagine what happens if the main OS is a D2 Delta but the bootloader is from the Fenix. Any update or cross-grade would never be installed as either the system wouldn't copy the firmware to the staging area (Fenix firmware rejected by D2 OS) or the bootloader wouldn't accept the file (D2 firmware rejected by Fenix bootloader). There's one user from early on who has a watch in this state and we never managed to fix it. Also Preboot mode doesn't work for him for some reason.

n.b.: Beta firmwares usually only have the main OS inside. So don't try to create a cross-grade version from those.

Very helpful.

[Answered my own question. I was looking at the software for the wrong Fenix model with respect to 1014/1015.]

All said if I understand correctly then that I just need to rename f5P1300_to_D2Delta610.gcd to GUPDATE.gcd and drop the file onto the watch, where it should recognize the update, unless for some reason it is already at V21.0 where flashing the backdate first will permit updating to the D2Delta firmware.