Quote Originally Posted by GerryK View Post
4. By " 'system' stage " do you mean the word 'system' shows on the screen briefly while attempting to connect in preboot?

YES. The words 'system' and then the word 'Loading' shows on the screen briefly while attempting to connect in preboot

5.3 Device Manager where it should show as "GARMIN Device" even briefly if it does connect in preboot mode

YES. I had not noticed that. I heard the laptop 'beep' sound and Dev Manager update so I knew the usb port had seen the device for a tiny few moments.
I do see Dev Manager showing "GARMIN Device" briefly while trying to connect in preboot mode ( while 'system' and 'loading' displayed above 'Garmin' .
It's important that you understand and accept that it's not just attempting to connect in preboot while that displays on its screen and it's simultaneously recognized in Device Manager, in fact it is in preboot and it's also connected to the PC (albeit very briefly) when that happens.

5.4 Does it show anything else on the screen before leaving 'Loader' message then powering off? Like a calibration screen with white dots and a grid?

NO
It goes back to ''Garmin' , garmin disappears , 'GARMIN' again and so on until i disconnect usb cable and power button off.
So this is why i ask so many questions, that information is crucial and determines that it's bootlooping. Why you don't see a calibration screen is because it's not even staying in preboot long enough to exit that mode normally (after some seconds) and then go into calibration mode. Unfortunately a bootlooping device is the most difficult to flash (i) because you first have to 'catch' preboot, and (ii) because it then it spends so little time in preboot before it's interrupted (i.e. it gets 'overridden' by the device's bootlooping cycle). The logistics are of course to first gain preboot and then to very quickly initiate a flash while in that extremely brief window-of-opportunity while it's actually still in preboot. That time window to start a flash may be barely a blink of the eye so you have to be very quick and also lucky. That means organized beforehand and very focused and disciplined. It may take many dozens of attempts or you might fluke it quickly. But patience is key, eventually you'll get it. The good news is once the flash commences by Updater.exe sending data to it that the bootloop is suspended and the device will then stay in preboot until the flash is finished. When Cure fw is loaded successfully, the device will be frozen on the splash screen with Mass Storage Mode re-enabled. You can then look for faulty files to remove (likely it's the detail map in this case, i forgot to ask you before if you see 'Loading Maps' briefly on the bottom of the screen just before the point where the screen blanks).

7. If it is showing in Device Manager briefly as "GARMIN Device", it will also show in G7ToWin but will be held in preboot once G7ToWin properly recognizes it and exchanges data packets with it. Similarly to it being held in Updater.exe only after a flash is initiated.

I will try G7ToWin again tomorrow, so far no success, need a bit more time to learn how that works when i select usb interface.
It's up to you however i think you can safely assume that it's HWID is 2267. It will be as hard to catch the right moment for G7ToWin as it will be with Updater.exe so i know where i'd be spending my time in this case

8. YES
I was able to generate the GarminCure3 firmware "226701000590.rgn". This running Cure3 as an administrator. It created the *.rgn in the 'GarminCure3-40F78E54' sub folder .
Updater.exe runs too . I set it to use usb.
After about 5 tries I did not get to where Updater.exe acknowledged a usb connection while I was in the Garmin Satnav 'system' and 'loading' boot phases.
I will try this last step again some more tomorrow and update you.
..........
So now you need to be like a sniper going for a difficult shot. Follow the procedure below over and over until you start the flash. Much of it will seem overly-pedantic so please keep in mind that other users reading this thread faced with a similar bootloop problem may not have your level of experience:

  • Load the cure 226701000590.rgn into Updater.exe;
  • Enable the radio button for "USB Device", position mouse cursor over "OK" button and leave the GUI open and visible on the PC's desktop;
  • Connect a 'Known Good' USB cable directly (no hub) to the PC's USB port (use only USB2 if available rather than USB3 and if using a desktop use rear rather than front port);
  • Mark the screen temporarily so you know the exact position to hold later. Ensure the device is fully OFF. Hold the power button down to force it off
  • Hold the screen firmly (left thumb works best for me usually) and plug the USB cable into the device's socket with your right hand and quickly move it to the mouse while watching the window next to 'USB Device';

(This is where it gets interesting and you must move very quickly)
  • The instant you see the device information appear in the window next to 'USB Device' Click 'OK' button on the GUI and keep the firm steady pressure on the device screen.

If you catch the moment right then the flash will proceed and Updater will eventually give the 'Success' message. If you fail the device details will disappear from the GUI and Updater will report an error. Start again, rinse and repeat over and over.