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This page is a portion of the Quick Start for Balsa. It tells you how to turn an ordinary SD card into a Balsa SD card using a Windows computer. The steps are:

  • Step 1. Download the image file for the Balsa SD card.
  • Step 2. Check the image file.
  • Step 3. Extract the image (.img) file using 7-Zip.
  • Step 4. Copy the image to an SD card. This action writes over the SD card completely. Any existing data on the card will be lost.

The download is about 1.1 gigabytes of data.

Step 1. Download the Image File

Download the Balsa SD card image. This will create a large .7z file on your computer.

Remember the folder that you’ve downloaded it to. You will need it later. Your browser/downloader probably has an Open containing folder option if you right-click on the download in the downloader window. You can use that to remember.

Download for Balsa Precise 1.7 Beta-2 SD (7z | 1.1 GB)

Step 2. Check the Image File Using an MD5sum

After you’ve downloaded the Balsa image, you need to use an MD5sum to check to see that the file has downloaded correctly. For an explanation of this MD5sum, see the Addendum.

Instructions for Checking the Image

  1. Download the MD5sums program. The download puts a .zip file on your computer.
  2. Use Windows Explorer to navigate to this file. Right-click on the zip file and choose Extract All. When you see the check box that says Show extracted files, be sure that it is checked.
  3. Windows Explorer will open with a folder containing the md5sums(.exe) program.
  4. Open another Windows Explorer window to the folder that contains your copy of the .7z Balsa image (the folder you remembered when you downloaded the Balsa SD card image in step 1).
  5. Drag the Balsa image file icon for the .7z file from one window and drop it onto the icon for the md5sums program in the other window. The md5sums program will calculate the MD5 hexadecimal number for your Balsa image file and display it in a window.
  6. Click this link: Balsa Precise 1.7 beta-2 version MD5. It will display the desired MD5 hexadecimal number.
  7. If the MD5 numbers/letters are the same (you have to check only the first few) the download was good. If you aren’t going to download another large image you can delete the md5sums program and proceed to Step 3.
  8. If the MD5sum numbers are different, there was a problem with the download, and you should download the image file again.

Step 3. Extract the Image Using 7-Zip

The Balsa image was compressed using a program called 7-Zip. Here is how to extract the full Balsa image file using 7-Zip.

  1. Download the 7-Zip program from You will probably want the version for Windows-32.
  2. Run the download to install 7-Zip in Windows.
  3. Run 7-Zip (also known as 7-Zip File Manager) from the start menu. Navigate to and select the Balsa image (.7z file) that you downloaded. Extract the .img file contained in it.

When it finishes, you will have an extracted Balsa image (.img) file, just under 8 gigabytes, on your computer. Now that you have the extracted image file you can make multiple Balsa SD cards with it. The file is very large so if you need the space on your computer you can just keep the compressed Balsa image (.7z file) and use 7-Zip to extract it when you want to make a new Balsa SD card.

Step 4. Copy the Image to an SD Card

When you have an extracted Balsa image (.img) file, the next step is to copy the image to the SD card, with the Win32DiskImager program.

  1. Plug in the SD card and take note of its drive letter. If a window opened for the card, close it.
  2. Download the Win32DiskImager program. The download puts the file on your computer.
  3. Use Windows Explorer to navigate to this file. Right-click on the zip file and choose Extract All. Make sure the check box that says Show extracted files is checked.
  4. Windows Explorer will open with a folder containing the Win32DiskImager program.
  5. Double-click Win32DiskImager.exe to run it. The program allows you to select an .img file and a device to copy to, as follows….
  6. In the Win32DiskImager program, for the Image File, navigate to the extracted Balsa image (.img) file that 7-Zip made.
  7. In the Win32DiskImager program, for the Device, select the drive for the SD card.
  8. Click on the Write button.
  9. The Win32DiskImager program will warn you that you may corrupt the drive. This is because it will overwrite everything on the SD card and any existing data will be lost.
  10. Let the program proceed.

When the Win32DiskImager program is finished, the SD card will be a Balsa SD card.

You can use the card to set up a machine to run Balsa, either the machine you just used to produce the card, or a different machine.

Addendum: Explanation of the MD5sum Check

The MD5sum is used to check to see if there’s an error in a large download. A number called an MD5sum can be calculated for any file. The MD5sum is unique to that file, and a small change in the file will make a completely different MD5sum. The number is normally written in hexadecimal, using 0-9 and A-F.

You download a small program that calculates the MD5sum of a file, and use it to calculate the MD5sum for your copy of the Balsa image. If your MD5sum is the same as the one we’ve calculated, you know your copy of Balsa image is the same as ours. If the two MD5sums aren’t the same, you know that the download had an error. Because even a small error makes a completely different MD5sum, you don’t have to check more than the first few letters and numbers.

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