Yes it's the Mediatek chip model so you can't do any conversions sorry. That's now the correct file to use for it, make the rgn from the gcd as i said, drag it onto Updater.exe, select the radio button next to 'USB Device' then connect the unit in pre-boot mode [not Mass Storage Mode]. To do that, turn nuvi off, hold the upper LH corner of the screen with your thumb, plug in usb lead which will fire up the unit. Keep holding the screen, when you see the device details appear in the window next to 'USB Device' press 'OK' on Updater's GUI or just hit Enter key on kb. Hold the screen at least until 'Software Loader' or similar appears on the unit's screen then let go. Make sure there's plenty of charge in the battery before you start, and make sure to do the nonvol backup and also reset it first.
Who told you about the LA Swamp Folk curse on the Tutorial Index?