Hi there,

I own a Garmin GPSMAP620 unit.
I like that device for his ruggedness and his large and high resolution screen but I can't suffer it's poor automotive firmware.

I'm not interested about the marine part of the firmware.

I would like to replace the original firmware with a better one, perhaps coming from one of the new units that use a 5" high resolution screen.

I read articles about replacing firmwares and I'm able to perform basic operations with rgntool and other utilities but I need some suggestions and/or instructions.

I really appreciate any help you can provide.