Data Hacking

FIGURE 6-19: Exiting the application
Chapter 6 — Hacking the Firmware
Using MeMap can be a little tricky, and because all firmware versions are different, there are no
hard and fast rules as to what you can and can’t do. Be careful and take your time. Mistakes can
happen, but you should be able to either rectify them or reload old firmware that will restore
your GPS to the condition that it was in before you attempted the changes. Because MeMap
only works on text within the firmware, the danger of a mistake causing major problems other
than just odd text on the screen is small.
Here are a few tips for you to get good results from using MeMap:
The most common edit that you will probably make is replacing an entire line of text in
the firmware. To do this, your search must start with the first character found in the firmware.
This is normally straightforward, but some lines begin with the copyright symbol ©.
In this case, you need to search for that. To do so, use an application that comes with
Windows called Character Map. Select Start ➪ Run, type in charmap, and then click
OK. Find the © character, select it, and copy it. Then switch to MeMap, select the search
text, and then paste the © in by holding down the Ctrl key while pressing the V key.
Uppercase characters are generally easier to read than lowercase characters.
To center a line of text, add spaces in front of the text.
Try to use the same number of lines of text that were originally used in your existing
firmware, as this reduces the potential for problems.
Manual Firmware Editing
You don’t actually need a special application to help you alter the firmware to customize the
text that is displayed on the GPS. All you need for this is a hex editor. A hex editor is a program
that enables you to open and edit a file represented in hexadecimal format.
I will be using a hex editor called UltraEdit available from www.ultraedit.com. UltraEdit
is a shareware application (a very good one in fact), but if you want something free instead, you
could try XVI32, available from www.chmaas.handshake.de.
Hexadecimal is a counting system that counts from zero to 16 instead of zero to 10, as in the
base 10 decimal system that we’re familiar and comfortable with. Counting to 16 is useful in
computer applications because it enables you to represent any byte (we’ll get to that in a moment)
with only two characters.
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