I tried loading a custom map onto my gpsmap 64st. The file must have been corrupted, or something... Now when I try to boot the device, the boot starts but after the "loading waypoints, tracks and routes" message, it powers itself down.
I have tried a master reset. It seems to go through the reset, but this has no effect on the problem.
The Garmin support site says to force the device into mass storage mode, but this doesn't seem to be working. The instructions are to connect the device while holding the up button. If I do this, my computer (Windows 7) makes the noise that indicates that a USB device has been inserted, nothing happens for 30 seconds or so, then the computer makes the USB-device-removed sound, and the gps then proceeds as before.
I have tried to do a "boot block", again, it doesn't seem to have any impact on the problem.
Where did you get that "custom map"? Maybe they can help?
It was a .kwz file saved from Google Maps.
From what I've read since, the Garmin software is rather fragile -- if you give it a corrupted file, it may crash. It's possible this file just didn't get properly written to the device before I unplugged it. I *thought* I did the unmount (eject) before I removed the gps, but the most likely explanation I have is that I messed that up. Or maybe I just misunderstood the instructions for creating custom maps.
For future reference: don't put any custom maps in the gps memory; put them on the SD card. You can just pull out the SD card if the map gives you trouble.