GarminCure3 tool - the new way to create cure firmwares for Garmin devices

**kunix** · 28th June 2013, 08:11 AM

Originally Posted by steveor

Up until a week ago I didn't even know about pre-booting Garmins. What does it actually do to the device and how does the GarminCure3 aid in recovering a corrupted device?

GarminCure3 exploits the way fw_all.bin enters the mass storage mode. First, fw_all.bin boots almost completely, while loading maps and other files and writing the info about them to GarminDevice.xml (this info is used later by WebUpdater), and then it "reboots" itself with register R12=0xC. Second, after the reboot fw_all.bin enters the mass storage mode while not reading any files (though, it does read NV).

Sadly, if some files are corrupted (or even worse, the entire partition is not recognized), fw_all.bin crashes before "rebooting". And no mass storage mode is available.

GarminCure3 patches fw_all.bin and makes it think that it was called with R12=0xC. In this case fw_all.bin enters the mass storage immediately, while not reading any files.
But if NV is severely corrupted, it could still crash. There are other methods which could help in this case, but they also need pre-boot mode.

steveor · 28th June 2013, 12:13 PM

Letting the device sit with the battery disconnected did not resolve the problem. The nuvi just goes into mass storage mode instead of pre-boot no matter what I do. Oh, well.

Originally Posted by kunix

But if NV is severely corrupted, it could still crash. There are other methods which could help in this case, but they also need pre-boot mode.

What is NV?

**kunix** · 28th June 2013, 12:40 PM

Originally Posted by steveor

Letting the device sit with the battery disconnected did not resolve the problem. The nuvi just goes into mass storage mode instead of pre-boot no matter what I do.

Maybe it's because of some hardware problem?

Originally Posted by steveor

What is NV?

NV is a region in flash chip where firmware stores lots of info. Also while in factory it's programmed with your UnitID. Pre-boot mode issues are not related to NV. You can erase it completely and pre-boot would still work.