2012-04-16 Zumo Memory

s many of us who own and use the (now old) workhorse Garmin Zumo 550 GPSes have come to realize, as the Map software update packages have continued to grow through the years, the relatively small 1.2 GB of internal memory in these units has become a limitation. It has come to the point that you can no longer fit the entire North America mapset onto your GPS. A complication of this situation is that, whenever the free memory is too small you will experience times when you cannot load any bigger route files and instead will get "Low Memory" errors.



There are all sorts of cumbersome workarounds for this problem. It's been well documented that there are a number of smaller files that can be (carefully) deleted from the GPS memory (non-English language files, voice files, extra vehicle icons, etc.) but the real problem is that, even if you only load a subset of the US states to the GPS, the map file itself is so big now that it monopolizes the GPS's memory. 



The best workaround that I've found was to not install the maps onto the GPS at all, but instead to just install your maps onto a big SD card.



When you initially install (or reinstall) a map version, the Map Update program allows you to choose whether to send the new map image file to the GPS, the GPS and your Computer, or just the Computer. You'll want to choose "Just the Computer" to get the full set of maps installed on your PC. If you can see and select the maps in Mapsource, they are installed on your PC. 



Before deleting anything, it's a good idea to make a full backup copy of all of the files on your GPS into a safe folder somewhere on your PC, just in case you ever want, or need, to backtrack. The only file that you'll really need to delete is the huge "gmapprom.img" from the GARMIN / Garmin directory of your GPS. You'll find that this file is about a full GB in size. This file will be the last version of maps that was installed onto the GPS. Leave all of the other files as they are. 



Using an 8GB SDHC card will allow you to load up the entire North America mapset plus 1000 MP3 songs (the most that can be indexed by a 550 anyway) and still have plenty of room to spare on the card. You can also use 16GB SDHC cards if you want, though they are a bit more expensive. If your PC doesn't already have a card reader built-in I would recommend getting and using a stand-alone card reader. Transferring the mapset files via USB 2.0 is much faster than the USB 1 interface built into the zumo.



You can either use the map select and transfer tools in Mapsource, or you can download and use the MapInstall utility from the Garmin website. I prefer the latter as the user interface is a bit simpler to use. The MapInstall user interface is pretty much intuitive. It allows you to select the device you want to send the maps to (in this case it will be your SD card) and you can select as much or as little of the map set as you want to use. You can also select maps from multiple mapsets, if for example you have both the regular City Navigator North America maps and also Topographic maps, like I do. 



Once you have selected all of the segments from each of the mapsets that you want to include, the MapInstall utility will crunch on them for quite a while (about an hour) and generate one very large supplemental map image file with the name of "gmapsupp.img", and then it transfer that file to the SD card. After it has finished, when you install the SD card into the GPS and power it on, it automatically finds that file just as if it were on the GPS itself. If you want to have multiple SD cards so that you can have different MP3s to listen to, you just need to copy the same gmapsupp.img file over to the new/additional SD cards and they will work equally well.



With the giant gmapprom.img file deleted from the GPS's memory, you'll have plenty of space so that you can keep as many saved Favorites, routes and tracklogs as you want on the GPS and still never get any Low Memory errors.