Garmin (Can I format Garmin itself ?)

Not recommended. Although some users have done this successfully and restored from a backup, many things can go wrong. It is a good way to "brick" your Garmin device (put it in a state where it won't boot or go into mass storage mode, making recovery difficult and sometimes impossible).

You certainly don't update your GPS by formatting it. You update it by downloading and installing Garmin Express on your PC, then connect the GPS to that PC via USB and follow the prompts.

http://software.garmin.com/en-US/express.html

Yikes!

YES you can format the internal storage area of your GaRmIn!!!

When the gArMIn is connected to your computer via an appropriate USB cable, it appears as a storage device including drive letter. I don't know how it appears when connected to as Apple.

Since it looks like a storage device, it can be formatted.

You likely won't like the results after the formatting completes.

But, like I said, the short answer is YES you can format it.

There have been quite a few topics on "Help! I accidentally formatted my nuvi".

Yup the devil made me do it. Spent hours recovering files with a recovery program to the point where I could log on to Garmin to re-install everything! So long ago I think it may have been my Nuvi 350. Never ever want to go through that again. This was also long before I heard of POI Factory probably even before it was founded..

Since then I always have the GPS backed up to my hard drive !

Yes you can format the Garmin GPS internal memory, but the real question is why would you want to?

To do a non-map update to a Garmin unit, as far as I've seen with numerous Garmin GPS units, one does not need to format the internal GPS memory.

Generally, unless one has a unit that is bricked or crashes, only time people mess with the internal memory is to delete the non critical files to create more space for map storage.

Formatting the GPS (in computer terms) wipes clean the operating system which is good for a computer, but detrimental for a Garmin GPS. There are ways to clear the user data back to factory fresh without formatting the device. Look for resetting your GPS here on the factory. Once the system has been formatted, there will no longer be a way for the Garmin unit to connect to your PC/Mac to be updated...

As others have stated, the correct way to update maps would be to load them from Garmin using the Garmin software.

I mentioned this earlier. It is like a Solid State Drive. (SSD) Does not need to be formated.