The TomTom One navigation system comes with, at most, a single gigabyte of memory. The standard amount of memory won't do, however, if you are going overseas and need the appropriate additional maps or if you wish to add after-market applications. Because the TomTom One lacks the slot needed to add an external SD card, you must modify its internal hardware by adding an internal SD card to increase the memory.
Back up all the data on your TomTom to your hard drive using TomTom Home by connecting your TomTom to your computer, opening TomTom Home and clicking "Back up and restore." Then click "Back up my device."
Press down on the eight tabs under the grey frame with a flathead screwdriver. There are two on each side.
Remove the frame once the tabs are disengaged.
Remove Phillips screws in each corner.
Disengage the four metal tabs on the top of the metal frame and the three on the bottom. They pop out just like the tabs on the grey frame you've already removed.
Remove the plastic ring from around the screen.
Pull the screen up so that it's standing on its bottom edge.
Pull out the thin metal band from the plug on the right side.
Remove the screen.
Install the SD card adaptor. The adaptor is the name for the slot that your new SD card will slide into. You will need to solder the wires from the interface to the correct pins. See References for a diagram showing the correct solder points.
Slide the SD card into the SD card adaptor.
Reassemble your TomTom.
Connect your TomTom to your computer via your USB port.
Open TomTom Home and click "Back up and restore." Click "Restore up my device." This will copy all the data on your hard drive to your TomTom.
Things You'll Need
Small flathead screwdriver
Small Phillips screwdriver
2 gigabyte SD card
SD card adaptor
A 2 gigabyte SD card is the maximum amount of memory you can add safely to your TomTom.
These steps will only work on TomTom One versions 1, 2 and all but the newest version of 3. Version 4 and the latest versions of 3 cannot have memory added because they lack the pins needed for soldering the SD card adaptor. Dismantle your TomTom before purchasing the SD card and the interface.