How to edit the boot configuration file for Raspberry Pi
A quick overview
While booting up, the Raspberry Pi reads some configuration parameters from the SD card. These parameters are stored in a file named config.txt. This file is within the part of the SD card which is visible to Windows PCs. Therefore, you can edit this configuration file from a Windows PC, from a Mac, from a Linux PC, or from within the Raspberry Pi itself.
This configuration file contains instructions which are necessary to setup the display. If you have severe problems with the display, you will need to connect the SD card to a PC so that you can edit the configuration file. If the display is working but you wish to make minor adjustments, you may find it more convenient to edit the file from within the Raspberry Pi itself.
How to edit from a Windows PC
This method is most useful if you cannot see anything on the display of the Raspberry Pi.
- Shut down your Raspberry Pi, remove the power and remove the SD card.
- Put the SD card in your PC's card reader and wait for the folder to open automatically.
- If the folder does not open automatically, open "My Computer" and then open the drive marked "SD".
- Look to see if there is a file called config (or possibly config.txt).
- If this file exists, open it with Notepad. If not, create the file with Notepad.
(One way to do this, in XP, is to right-click where you see the other files, select New and then Text document. Then change "New Text Document" to "config").
- Open config.txt using Notepad, and add the necessary configuration parameters.
- Save the file (menu item File, Save)
- Exit Notepad
- In Windows Explorer, go to "My Computer". Right-click on the SD card and select "Safely Remove".
- Remove the SD card from the PC and insert it in the Raspberry Pi.
How to edit from OSX
▪ Shut down your Raspberry Pi, remove the power and remove the SD card. ▪ Put the SD card in your Mac's card reader and wait for the card to appear on the Desktop. ▪ Open the card in Finder. ▪ Look to see if there is a file called config (or possibly config.txt). ▪ If this file exists, open it with TextEdit. If not, create a new file in Textedit as Plain Text format. ▪ Add the necessary configuration parameters. ▪ Save the file as "config" and quit TextEdit. ▪ In Finder eject the SD card by dragging it to the Trash or clicking the eject button in the Finder window. ▪ Remove the SD card from the PC and insert it in the Raspberry Pi.
How to edit from the Raspberry Pi
- Reboot the Raspberry Pi and enter your username and password.
- To edit the configuration file, enter the command
sudo nano /boot/config.txt
- Type in the necessary configuration parameters
- Save the edited file
Press Control-x Press y Press [enter]
- After exiting the editor, restart using the command
An example configuration file
This example show how to reduce the size of the display to prevent text spilling off the edge of the screen.
overscan_left=20 overscan_right=20 overscan_top=20 overscan_bottom=20
What configuration options are available?
For a list of all the configuration options available, click here