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Writing an SD Card on Windows with WinFlashTool

This page details how to write a Raspberry Pi operating system .img file to an SD card using a tool called WinFlashTool.

I have found this tool to be very accessible on Windows using the NVDA screen-reader.

First you will need to download WinFlashTool and install it.

You will also need some way of mounting the SD card on your Windows machine. USB SD card readers are good for this if your computer does not have either an SD or micro-SD card slot.

You will need to use a full size SD card for the older type of Raspberry Pi, or a micro-SD card for the Model B+ or version 2 Model B+.

Dealers who sell micro-SD cards often include a micro-SD to SD adaptor with the purchase of a micro-SD card. These are useful if your card-reader only takes full-size SD cards.

It is important to note that just copying, or using drag-and-drop to put a .img file onto an SD card will not work. The file needs to be written to the card byte-for-byte.

Also note that if a .img file has previously been written to the card, only one of the 2 or more disk partitions on the card will be recognised by Windows. This is because the boot partition is FAT32, which Windows can read, and the other partitions on the card are Linux partitions which Windows is not capable of reading.

Once you have installed WinFlashTool on your Windows machine, follow these steps:

  1. Open WinFlashTool using the start menu or however you usually launch programs.
  2. You will hear something like source image grouping and the text field that has focus is for the name of the .img file to write to the card.
  3. If you press the TAB key at this point you will hear something like ... button. This is the browse button which will open the file-finder dialog for you to locate your file. Or you can just type the full path and file-name into the first text box.
  4. The next control is a list of the devices on your computer. It will give you a list you can navigate up and down with the up and down arrow keys. But see the next item on this list for a way to hide your hard-disk and avoid the nasty accidental over-writing of your system.
  5. The next control to gain focus when you press the TAB key is a checkbox which allows you to hide devices that are not replaceable media. Checking this box is a good idea as it will prevent you from accidentally writing the .img file to your hard disk. And you don't want that to happen.
  6. Next control is the write button. Which will begin the write.


When you begin the write, Windows will pop-up after a couple of minutes and tell you that you need to reformat the drive. Just cancel out of this as the write will not continue until you do.

When the write is complete you might get another pop-up of the open folder to view files variety.
Again, ignore this nonsense.

At this point you can close WinFlashTool, remove the card from it's slot or holder, insert it into your Raspberry Pi and boot it.

If the file was a valid operating system that is bootable, and if the write has worked correctly, the Pi should boot.


This guide is correct in my experience of WinFlashTool. However I do not guarantee fitness for purpose and I cannot be held responsible for loss or damage to data produced by following this guide, either to the letter or erroneously. It is possible to over-write the boot-sector of your primary disk partition using this tool, thus rendering your Windows machine unbootable.

You have been warned.