Thread: MARQ Commander (Gen 1) stuck in recovery loop – WebUpdater rejects official firmware

Hello,

I'm trying to recover a Garmin MARQ Commander (1st generation) and would appreciate some advice from anyone familiar with the Fenix 6 / MARQ firmware architecture.

From reading several discussions, I understand that the Fenix 6 / MARQ generation uses a different firmware layout than older Garmin devices, so GarminCure3 cannot patch these firmwares.

Is there currently any recovery method for this platform?

Any advice would be greatly appreciated.

Thank you.


Here is the description of the symptoms and what I have done so far.

The watch entered this state after the battery became completely discharged.

The boot sequence is always identical:

MARQ
↓
GARMIN
↓
Copyright © 2019 Garmin Ltd.
↓
Converting GPX files...
↓
Loading FIT files...
↓
Automatic reboot

The entire cycle takes approximately 10-12 hours before restarting.

The behaviour is completely deterministic, I have repeated it already 5 times at least.

What has been done

I have already replaced the original battery with a brand-new Cellonic battery.
The replacement battery powers the watch for the full 10-hour cycle.
Therefore the boot loop is independent of the battery.
The watch is able to run from battery alone.

I can reliably enter preboot mode.

Windows detects the device as: VID_091E & PID_0003

Garmin WebUpdater detects the watch as: MARQ MARQ V03.40 (Unit ID 0)

WebUpdater offers firmware 20.50 (13.9 MB).

After pressing Update, a progress bar appears briefly and then WebUpdater reports: "The update file is corrupted."

I downloaded the official firmware manually: MARQCommander_2050.gcd

Its SHA-256 is 9af93f19acb55d44b80436199f1f34452fc3fee64bd6e04e93f3f66dbe70e715

During the update, WebUpdater creates Update.RGN file which has the same exact hash value.

I have tried GarminCure3 which reports: No patchable HWIDs detected.

and RGN_Tool that shows HWID = N/A

Just to add a few more observations for completeness:

WebUpdater downloads the official firmware as Update.RGN, but the file is byte-for-byte identical (same SHA-256) to the official MARQCommander_2050.gcd downloaded from Garmin.

When using WebUpdater in the normal way, it reports: "The update file is corrupted."
However, when I launch WebUpdater by explicitly passing the official .gcd file on the command line (or by dragging the .gcd onto the executable), I get a different error: "Garmin device cannot program the required memory region."