Website to download free firmware and map updates for Garmin GPS navigator

Garmin provides free firmware update and maps update (if applicable) for their series of GPS navigator products.

Before you can perform the updates, here are the prerequisites:

• You need a suitable USB cable to connect your Garmin GPS to your computer.
• You need to have internet access.
• You need to create a user account and register your product in the Garmin customer support website.
• You need to download and install the Garmin Communicator Plugin Software to allow Garmin customer support website to be able to communicate with your Garmin GPS via your web browser.

After you login the Garmin customer support website and registered your GPS product, just go to the myDashboard tab and you'll find the section to update your firmware (software) as well as your maps that eligible for update with Garmin.

If your Garmin GPS is a localized Sing/Mal or India product, you can also download the update file from their Singapore customer support website which does not need to create any user account nor install the Garmin Communicator Plugin Software.

• Click here to go to Garmin localized products software update webpage.
• Click here to go to Garmin localized products free map update webpage.

Step by step instruction will be provided on how to perform the update.

Alternatively, you can also perform software update by using the Garmin WebUpdater application. This application will help you perform the update easily in a step-by-step manner.

As normally advised, always backup all the important content in the flash memory of your GPS before you perform any update to the software or to the maps. A copy-and-paste from the GPS flash memory to a folder in your computer will do.

Adding multiple maps in Garmin Nuvi 255w GPS

Theoretically, the Garmin Nuvi GPS navigator can be loaded with hundreds of map. The limit is on the maximum file size (about 2GB per file) and available storage memory.

The maps are stored in specific mapset files with *.img extension in the flash memory of the GPS unit. Each mapset file contains one or many maps in it. Beside that, the Garmin GPS navigator can also recognise and load up one additional mapset file from SD card residing in the "Garmin" folder and named as "gmapsupp.img".

Here are the mapset files supported by Garmin Nuvi 255w GPS navigator:

• gmapbmap.img - the default base map
• gmapprom.img - the primary mapset
• gmapprom1.img - the secondary mapset
• gmapoem.img - the OEM mapset that cannot be unselect by user (if it exist)
• gmapsupp.img - the supplemental mapset which you can have one in the GPS flash memory and another one in the attached SD card.

Therefore, the Garmin Nuvi 255w GPS supports up to 6 mapset files, including 1 in SD card. Normally new maps installed by the user will be stored in gmapsupp.img.

You will lost all the maps in the previous mapset file if it is overwritten by a new file with same filename. If you want to keep the existing maps, ensure that you store the mapset file with an unused filename (from the 5 filenames above). Alternatively, you can make use of special tools to merge new maps into existing mapset file.

You can view the name of your base map in Tools > Settings > System > About > Basemap.

You can view the name of maps in the other mapset files in Tools > Settings > Map > Map Info. There, you can tell the GPS to load the map by checking on its name, or not to use the map by unchecking it.

In case there are 2 or more non-overlaping maps available for the same location, the map with the highest priority number (defined in the map itself) will be used by the GPS.

Note that certain map which are locked by vendor need a 25 bytes unlock key stored in a *.unl file in the same folder and with the same name as the mapset file where the locked map is stored in.

You might probably also interested to read:

• Using GMapTool to combine multiple maps into one mapset file for Garmin GPS
• Using GMapTool with cGPSmapper to convert finalized gmapsupp.img back to MapSource maps

Accessing the built-in Diagnostic Utility in Garmin Nuvi 255w GPS

Just discovered that there is a "hidden" built-in Diagnostic Utility in Garmin Nuvi 255w GPS navigator.

You can access it by tapping on the battery icon on the upper right corner of the screen and hold for more than 5 seconds until the Diagnostic Utility come up. Here is how it looks like:

This built-in Diagnostic Utility allows you to see detail technical information of the GPS navigator and the attached SD card (if any). You can also use it to perform some test on its memory, voice, display, and other functions.