Thread: Help --- German 250W is bricked quite badly!!!!

I have successfully make software update for more than 20 Garmin Nüvi navigation devices (different model like 200, 250, 255, 250W, 255W, 760 765 1340, 1350 and 40 etc.) except this time when I update 250W. This device is bricked, but I made update like usually I did before.

1. Connect 250W to PC using Garmin USB cable, device turn on, PC recognized the device and go to Mass Storage Mode.
2. Use Garmin myDashboard download software. myDashboard detect new software version 7.60 can be install in this 250W model. (I know the last software for 250W is 4.00, I think this device has 255W mainboard, I also update one Garmin 250W before, which can install software 7.60 with HWID 827).
3. After download new software, click safely remove hardware button to quit Mass Storage Mode, the Garmin 250W automatically start up, screen show software loading. I keep device connect to PC via USB cable in order to avoid software update fail if battery power is low.
4. After software update, device go to Mass Storage Mode again (because still connect with PC via USB cable). Then I download some new voice and click safely remove hardware button to quit Mass Storage Mode, unplug USB cable.
5. Try to switch on Garmin 250W by shift power button to left, this Garmin can not power on. Now the Nuvi won't boot up at all, no error messages, nothing on screen, and screen keep black. Bring device into the very "dark" room. Turn it on and do not to see the light appear, no backlight from screen at all.
6. Plugged in automobile and home charger (both from Garmin), no response from unit.
7. Connect 250W to PC using Garmin USB cable again, device doesn't turn on, nothing on screen at all and did not recognized by PC.
8. Opened up my 250W, disconnected the internal battery and measured open circuit battery voltage with a voltmeter. Reading was 3.7 VDC
9. Try to enter pre boot mode by slide and hold the power button, then quickly plug in the USB cable to connect to the PC. Device can not enter pre boot mode, not recognized by updater.exe. Also try press and keep holding the most left upper corner of the LCD screen by plug in USB cable, no successful. Main problem is I am not able to power on this device. Anyone knows other method to enter pre boot mode.
10. Of course, can not use g7towin to get any information connecting this device (I guess HWID is 827, because I can update software to version 7.60).
11. So it seems the 255w is bricked quite badly and can't enter pre boot mode. Any thoughts if it is possible to recover?

Any suggestions would be greatly appreciated.

Thank you,