I have killed three arduinos, one of them just trying to customize it (show my own vendor id, use “my” own drivers, etc). So I wrote a small tutorial about how customize it:
Initially, your board (any arduino) must look this way in Windows device manager:
Download, unzip and run MPROG: http://www.ftdichip.com/Resources/Utilities/MProg3.5.zip
Download the default configuration for the FTDI chip from here:
Arduino Playground - FTDI (direct link: Arduino Playground - HomePage)
Load that configuration in Mprog. You will see something like this:
Enter EDIT MODE with Ctrl+D in Mprog (or click the third toolbar button), now change the USB VID / PID from "FTDI DEFAULT" to Own VID & PID. Set new values for Vendor ID and Product ID.
Down, you can change the Manufacturer name and Product description. My changes look this way (is for my Freeduino):
Now, (save this configuration if you wish) click Device / Scan. Your board must be connected and installed as usual. Below you will see "1 programmed device". To reprogram your ftdi just click Device / Program.
Status after "Device / Scan":
Ready, unplug your board. Now you must modify the FTDI driver:
Check http://www.ftdichip.com/Drivers/D2XX.htm
You can use the zip (http://www.ftdichip.com/Drivers/CDM/CDM%202.04.16%20WHQL%20Certified.zip) or the installer package. I will use the exe one (http://www.ftdichip.com/Drivers/CDM/CDM%202.04.16.exe).
After the first driver installation, go to Windows %TEMP% (open "%temp%" from start menu) and look for a ckz_XXXX folder like this:
Copy the contents of this folder. This will be your custom driver installation.
Open ftdibus.inf and ftdiport.inf files and seek for
"VID_0403&PID_6001"
Replace using your own VID and PID, in my case by:
"VID_0666&PID_5001"
Look for some strings like this:
[Strings]
FTDI="FTDI"
DESC="CDM Driver Package"
DriversDisk="FTDI USB Drivers Disk"
In both files you can type anything you want.
Now, edit the "dpinst.xml" file. You can know more of how this file works here: Microsoft Learn: Build skills that open doors in your career (look here to know about language code, because maybe my 0xC0A spanish code will don't work on your machine)
I have used the ftdi's template:
<?xml version="1.0"?>
<dpInst>
<language code="0xC0A">
<dpinstTitle>Instalador de Freeduino v1.16</dpinstTitle>
<welcomeTitle>Bienvenido al asistente de instalación de los controladores para la placa Freeduino</welcomeTitle>
<welcomeIntro>Este asistente instalará los controladores de la placa Freeduino v1.16 para Windows.</welcomeIntro>
<eulaHeaderTitle>End User License Agreement</eulaHeaderTitle>
<eulaYesButton>I &accept this EULA</eulaYesButton>
<eulaNoButton>I do &not accept this EULA</eulaNoButton>
<installHeaderTitle>Installing the software for your FTDI device...</installHeaderTitle>
<finishTitle>Congratulations! You are finished installing your FTDI device.</finishTitle>
<finishText>VCP drivers are now installed for your FTDI USB device.</finishText>
<eula type="txt" path="eula.txt" />
</language>
<icon>ftdismall.ico</icon>
<watermarkPath>FTDI.bmp</watermarkPath>
</dpInst>
My customized files are here:
http://servicios.ried.cl/custom_ftdi_arduino.rar
I have created a good looking freeduino icon and a resource-modified winrar sfx installer:
Installation process:
http://screencast.com/t/QjWCaerG
We are ready now, plug in your modified arduino to see the results. You might ask how will my Freeduino looks now:
Installation (some warnings will appear because I didn't pay to microsoft to get my custom ftdi drivers digitally signed :-/):
And from Device manager:
Good look!
PD: All of my broken arduinos are alive now 
(ftdi transplant ::))
