Quote Originally Posted by hodgo View Post
newbie, here with a failed firmware upload.
1) Bricked device: Montana 610 , Firmware version:failed to update 3.50, HWID - 39xxxxxxxx.
That's your device's unique 10 numeral Unit Identification (UID), not it's HWID which consists of only four numerals. Being as you're in Oz if you purchased it new locally it'll be HWID 2299. Seems you can access preboot so you can check it's HWID with G7ToWin. You should remove your UID from your post for privacy as it's possible to use it for cloning.

2) used basecamp to update firmware. After restarting garmin did the "validating update" screen, gets to somewhere between 22% and 31% and screen fades off
It appears to be soft-bricked because of a corrupt GCD file.

4) Does your pc sees your device: very briefly with basecamp not GE, and only if i hold power button depressed
It's going into preboot when you hold the power button down but it doesn't stay in preboot for long unless a flash is initiated by Updater.exe in which case it holds preboot.

7) If you don't know HWID get it by Use program G7ToWin to retrieve your HWID - trying that now
It's essential you confirm your HWID is 2299 before proceeding.

8) Write down if you already read or tried GarminCure3 tool - giving this a go once i figure out HWID
Post again if you need more help after trying with cure firmware to reach Mass Storage Mode. You'll likely only need to delete the corrupt GUPDATE.GCD file from the device then load original fw to restore it. You probably won't need to re-format the internal drive.

9) Can you reach preboot mode? sounds like i did accidentally.
Yup.