I tried doing it using the Garmin Cure, but I get the message:

I downloaded a .rgn Nuvi8xx_regionfileonly_470.rgn and tried using it in GarminCure3 which I then got an error message.

Processing C:\Users\Eric\Desktop\Garmin\nuvi8xx_regionfileonly__470.rgn
This is a RGN file.
got an exception:
XRgnSection::Load(): REGION_HEADER.const52!=0x52 at offset=0000002D

Processing FAILED

DO you have any link for a step by step guide to use the Updater.exe?

Thanks