Modifying a USB to Work Like a U3 Drive




Note: It's been about 4 years since I put this Instructable up, I recently got a few requests to fix the broken links. That should be all done :)

Hey guys,
One of my recent projects was to venture to the shops and return with the holy grail of USB devices:
A U3 Drive
The price for these devices is pretty outrageous. A U3 drive, with half the storage of the equivalent Lexar drive was twice the price! So I went with the Lexar. When I got home, I did some playing with my 8GB Lexar thumbdrive.
I managed to get the drive functioning like a normal U3 drive and I've encapsulated the how to into this instructable.

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Step 1: What You'll Need

Your going to need the following:
A USB drive
And this

Step 2: Now for the Numbers

Okay, now open up USBDeView and find your drive. Then double click it and another menu will appear, search for the Vendor ID and take note. If the Vendor ID is only numbers then download this.
If it has letters, then download this.
If your not sure, try both.

Step 3: Using UFDisk

If you using UFDisk(First Download) then insert your USB, open the program, click AutoRun and set the slider to anything bigger than a megabyte. Then select the image.iso you downloaded earlier and click make.
Okay! that was the hard bit, now for the easy bit! Please skip to step 5.

Step 4: Using UCDExec

Ok, here goes.
Set the AutoRun area size to1MB. set the image to the image.iso that you downloaded earlier. Click burn.

Step 5: Finally!!!

Okay, now that we have got our USB set up, ensure that you cycle the USB - That means to take out, and plug the USB back in. You should have seen both a CD drive AND a USB drive show up in 'My Computer' when you plug the USB back in. If you didn't, then you will have to do some searching for the program appropriate for your USB.

Go onto the USB (Not the CD Drive) and add a file called 'fake-u3.ini' (without the quotes). Open up the file you just made with notepad and write into there:

\(Program you want to run; even a directory to a program)

so for me, its:


Because I'm using the PortableApps suite. THE \ IS VERY IMPORTANT

Just so you know...

This is a very simple VB.NET program, it works by getting all the drives and searching for the 'fake-u3.ini' when it is found, it opens it and opens the EXE specified in the INI.

Also, you should be aware that this doesn't really work the way it did when I first wrote this instructable. Microsoft have disabled CD autorun, so you will have the same outcome as with an ordinary USB drive when running Windows 7 or higher.

Please Enjoy :)

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18 Discussions


2 years ago

Links are broken again, definitely need the iso to make this work. Anyone else have a dl to the iso?


2 years ago

Nope, "page not found" following the links!


2 years ago

When i try to run any program in step 2 it says that no device is found


3 years ago

So I did everything but just one cddrive and not both the cd drive and the usb drive... So what should I do now?

1 reply

Reply 3 years ago

As in only one cd drive appears, not both... I have tried everything.. Can someone help me, please? ^^


4 years ago on Introduction

When I click "Make" on UFDisk th green bar continues to the end then nothing. Is this right? So far, when I cycle my USB it just shows up as an unformatted drive..

Tried with UCDExec but it just says no device available.

3 replies

your .iso is missing. I am curious tho as to how you wrote the code to search for the specific .ini and execute the exe stated within. Id just like to search for a specific exe and execute it. There is another method to loading an ISO onto a u3 drive using the u3 install software itself but requires you to use Charles and direct the request to a local iso file. Ill work on a video tutorial sometime.

1 reply

8 years ago on Step 3

also does not seem to work in finding my U3 device.


8 years ago on Step 2

UCDExec app says it cannot find my device

My U3 works without any troubles