Thread: Need help: Bricked ZÅ«mo 590 after timezone update via Garmin Express

1) Device info
Model: Garmin ZÅ«mo 590
Product code: 006-B2079-00
Firmware: 3.3 (last known working version)
HWID: Unknown � the device reboots too fast to retrieve it. I'll try G7ToWin if I can ever get a stable connection.

2) How it got bricked
The device was connected to my Windows 11 PC when Garmin Express when I accepted a timezone update. The whole thing seemed done in under 15 seconds. Right after that, the device went into a bootloop and hasn't recovered since.

3) Symptoms
Continuous loop: brief Garmin logo → black screen → reboot. When I place my fingers on the top-left of the screen while connecting USB, it consistently shows "System" (scrolling) followed by "Loading" before resetting again.

4) Does your PC see the device?
On both my Windows 11 PC (Garmin Express v7.28.0) and an older Windows 8 PC (Garmin Express v7.13) I get the USB connect sound immediately followed by the disconnect sound. The device shows up for a split second but never appears as a drive in Explorer � the connection is just too short for any meaningful access.

5) What I've already tried

Long power hold (20�30s) → no effect
Removed SD card → no effect, same bootloop on internal memory
Hard reset (bottom-right finger press) → executes but doesn't fix the bootloop
Preboot attempt (top-left and top-right finger while connecting USB) → screen shows "System / Loading" then resets; might be entering preboot briefly but fails during loading
USB during bootloop on both PCs → momentary recognition only, drops before I can do anything
Multiple USB cables and ports, including a USB 2.0 hub on the Windows 11 PC → same behavior everywhere
Checked Express download folders and CoreService → no usable .gcd for this device found
Logs are available in C:\ProgramData\Garmin\CoreService\Logs\ and can be zipped and attached if useful
SD card recovery → not attempted yet, waiting for guidance before I try anything there

6) Garmin USB Drivers
Yes, installed on both machines.

7) HWID
Can't retrieve it due to the bootloop. Will try G7ToWin if I manage a stable connection. If anyone knows a way to grab the HWID during that brief connect window, I'd love to hear it.
8) GarminCure3 and n�vi unbrick guide
Read both. Couldn't find anything Zūmo 590-specific. As far as I can tell, both approaches need a stable USB connection to push cure firmware � which is exactly what I can't get right now. Happy to be corrected if I'm missing something.

9) Preboot mode
Possibly reachable. When I try the preboot combo the screen shows "System / Loading" then resets. I can't confirm a full preboot session since it fails during loading every time.

10) NV backup
No, I don't have one.

my questions
- Is there any hope of reviving?
- Is there a known EU/ENG 3.x GCD available for the ZÅ«mo 590? (I think I found one on the internet)
- Any tricks to reliably capture the HWID during that brief USB connect window?
- Is there a way to extract a usable GUPDATE.GCD from the manifest or small .img files that Express created?
- If cure firmware is needed, can someone point me to a trusted ZÅ«mo 590 cure or help me build one?
- If preboot is reachable, what exact timing or button combo keeps it stable long enough for a cure flash?
- I haven't tried SD card recovery yet � can someone walk me through using a 3.x GCD safely, or advise where to get a reliable EU/ENG one?