Sorry, I've checked further. BMW Navigator IV and zumo 660 are actually identical hardware and accordingly they have the same HWID 0924. They use the same firmware and attaining preboot is also the same. You can read this thread about similar problems for a zumo 660 getting into pre-boot: [Only registered and activated users can see links. ]. That user finally succeeded after multiple methods and attempts.

If you haven't got an RGN file then you cannot flash in pre-boot using Updater.exe. Any GCD or EXE version of firmware can't be flashed that way. I think you need to back up a bit and get things right from the start and I would try initially to re-flash ORIGINAL firmware before you try a modified Cure firmware. That may fix your problem but only if it's due to faulty firmware. If a problem relates to a corrupt file stopping the device booting that's what Cure firmware is for, it allows bypass of loading files on boot and attaining Mass Storage Mode to delete files in MSM or to reformat it. You don't have that situation as your device boots up fully. If you wish to try reloading standard firmware then follow this:

1. Make an RGN file from the GUPDATE.GCD file [to find it, use an extraction soft like Universal Extractor/7-Zip/WinRar etc to extract "BMWMotorradNavigatorIV_350.exe". Look inside the folder named 'zumo' for another named 'Garmin' and in there is the GCD file]. If you need the GCD then go here to get the EXE:
Code:
Please Login or Register to see the links
2. Open the GCD in RGN_Tool and press the RGN button:

[Only registered and activated users can see links. ]

3. Name the RGN file only as 092401000350.rgn (no other naming is safe).

4. Open the RGN in Updater.exe and enable the radio button next to USB Device:

[Only registered and activated users can see links. ]

5. Now place the device into pre-boot and immediately the window is populated press OK or hit Enter. Keep holding until flash is finished.

There is a very big possibility that there's a problem on the PCB or the USB socket which is why there's no connection to PC. If you cannot get into either pre-boot or MSM then that's likely the problem. No software method can fix a hardware problem of course.

Other considerations:
  • Use only a rear USB port on PC.
  • Although you've tried 3 different cables try more, sometimes even Garmin branded cables can be finicky.
  • Move the USB plug gently around in the socket to see if the PC suddenly recognizes it in MSM (listen for the Windows ding connection sound). Unless you've reflowed the USB soldering to the board it's quite possible there is a microscopic break in a connection. You've said it was seen briefly by the PC once.
  • Carefully inspect the USB socket for a bent or broken pin.


The symptom of charging but not having any PC recognition is highly indicative of damaged USB socket/board connection.