The parameters available for the config.txt file will be listed in this wiki. Please note that you edit this file at your own risk, and some settings may harm your device if used incorrectly. Warnings will be listed where appropriate in the following text.

The config.txt file is a collection of property:value pairs. Unless otherwise stated, the first parameter in each section is the default property. Its placed in /boot/config.txt

Details in this wiki have been adapted for easier reading from the works here: http://elinux.org/RPi_config.txt

Video Mode

sdtv_mode

Used to set the standard for composite output.

sdtv_mode=0    Normal NTSC
sdtv_mode=1    Japanese version of NTSC – no pedestal
sdtv_mode=2    Normal PAL
sdtv_mode=3    Brazilian version of PAL

sdtv_aspect

The aspect ratio for composite output.

sdtv_aspect=1  4:3
sdtv_aspect=2  14:9
sdtv_aspect=3  16:9

sdtv_disable_colourburst

Disables colour burst on composite output. Although the picture will be monochrome, it may be sharper.

sdtv_disable_colourburst=1

hdmi_safe

Use "safe mode" settings to try to boot with maximum hdmi compatibility.

hdmi_safe=1

This is the same as adding the following lines together:

hdmi_force_hotplug=1 
config_hdmi_boost=4
hdmi_group=1
hdmi_mode=1
disable_overscan=0

hdmi_ignore_edid

Enables the ignoring of EDID/display data

hdmi_ignore_edid=0xa5000080

hdmi_force_edid_audio

Pretends all audio formats are supported by display, allowing passthrough of DTS/AC3 even when not reported as supported.

hdmi_force_edid_audio=1

hdmi_ignore_cec

Pretends CEC is not supported by TV. Avoids bringing (CEC enabled) TV out of standby and channel switch when rebooting.

hdmi_ignore_cec=1

hdmi_force_hotplug

Pretends HDMI hotplug signal is asserted so it appears a HDMI display is attached

hdmi_force_hotplug=1 Use HDMI mode even if no HDMI monitor is detected

hdmi_ignore_hotplug

Pretends HDMI hotplug signal is not asserted so it appears a HDMI display is not attached

hdmi_ignore_hotplug=1 Use composite mode even if HDMI monitor is detected

hdmi_drive

Chooses between HDMI and DVI modes. DVI mode will mean that sound is not transmitted though HDMI. Normal mode will transmit sound if supported.

hdmi_drive= 1 Normal DVI mode 
hdmi_drive= 2 Normal HDMI mode 

hdmi_group

Defines the HDMI type. This is used by hdmi_mode. Not specifying the group, or setting to 0 will use the preferred group reported by the edid.

hdmi_group=1   CEA
hdmi_group=2   DMT

CEA:

Electronic Industries Alliance (EIA-861B) refers to a CEA/EIA standard which consists of display timing and formats supported by Digital Televisions

DMT:

Display Monitor Timings (DMT) are a list of VESA standard pre-defined timings which are commonly used within the Computer industry.

hdmi_mode

Defines screen resolution in CEA or DMT format. The following options are supported:

hdmi_group=1 (CEA):

hdmi_mode=1    VGA
hdmi_mode=2    480p  60Hz
hdmi_mode=3    480p  60Hz  H
hdmi_mode=4    720p  60Hz
hdmi_mode=5    1080i 60Hz
hdmi_mode=6    480i  60Hz
hdmi_mode=7    480i  60Hz  H
hdmi_mode=8    240p  60Hz
hdmi_mode=9    240p  60Hz  H
hdmi_mode=10   480i  60Hz  4x
hdmi_mode=11   480i  60Hz  4x H
hdmi_mode=12   240p  60Hz  4x
hdmi_mode=13   240p  60Hz  4x H
hdmi_mode=14   480p  60Hz  2x
hdmi_mode=15   480p  60Hz  2x H
hdmi_mode=16   1080p 60Hz
hdmi_mode=17   576p  50Hz
hdmi_mode=18   576p  50Hz  H
hdmi_mode=19   720p  50Hz
hdmi_mode=20   1080i 50Hz
hdmi_mode=21   576i  50Hz
hdmi_mode=22   576i  50Hz  H
hdmi_mode=23   288p  50Hz
hdmi_mode=24   288p  50Hz  H
hdmi_mode=25   576i  50Hz  4x
hdmi_mode=26   576i  50Hz  4x H
hdmi_mode=27   288p  50Hz  4x
hdmi_mode=28   288p  50Hz  4x H
hdmi_mode=29   576p  50Hz  2x
hdmi_mode=30   576p  50Hz  2x H
hdmi_mode=31   1080p 50Hz
hdmi_mode=32   1080p 24Hz
hdmi_mode=33   1080p 25Hz
hdmi_mode=34   1080p 30Hz
hdmi_mode=35   480p  60Hz  4x
hdmi_mode=36   480p  60Hz  4xH
hdmi_mode=37   576p  50Hz  4x
hdmi_mode=38   576p  50Hz  4x H
hdmi_mode=39   1080i 50Hz  reduced blanking
hdmi_mode=40   1080i 100Hz
hdmi_mode=41   720p  100Hz
hdmi_mode=42   576p  100Hz
hdmi_mode=43   576p  100Hz H
hdmi_mode=44   576i  100Hz
hdmi_mode=45   576i  100Hz H
hdmi_mode=46   1080i 120Hz
hdmi_mode=47   720p  120Hz
hdmi_mode=48   480p  120Hz
hdmi_mode=49   480p  120Hz H
hdmi_mode=50   480i  120Hz
hdmi_mode=51   480i  120Hz H
hdmi_mode=52   576p  200Hz
hdmi_mode=53   576p  200Hz H
hdmi_mode=54   576i  200Hz
hdmi_mode=55   576i  200Hz H
hdmi_mode=56   480p  240Hz
hdmi_mode=57   480p  240Hz H
hdmi_mode=58   480i  240Hz
hdmi_mode=59   480i  240Hz H

Note:

• H means 16:9 variant (of a normally 4:3 mode).

• 2x means pixel doubled (i.e. higher clock rate, with each pixel repeated twice)

• 4x means pixel quadrupled (i.e. higher clock rate, with each pixel repeated four times)

hdmi_group=2 (DMT):

hdmi_mode=1    640x350   85Hz
hdmi_mode=2    640x400   85Hz
hdmi_mode=3    720x400   85Hz
hdmi_mode=4    640x480   60Hz
hdmi_mode=5    640x480   72Hz
hdmi_mode=6    640x480   75Hz
hdmi_mode=7    640x480   85Hz
hdmi_mode=8    800x600   56Hz
hdmi_mode=9    800x600   60Hz
hdmi_mode=10   800x600   72Hz
hdmi_mode=11   800x600   75Hz
hdmi_mode=12   800x600   85Hz
hdmi_mode=13   800x600   120Hz
hdmi_mode=14   848x480   60Hz
hdmi_mode=15   1024x768  43Hz  DO NOT USE
hdmi_mode=16   1024x768  60Hz
hdmi_mode=17   1024x768  70Hz
hdmi_mode=18   1024x768  75Hz
hdmi_mode=19   1024x768  85Hz
hdmi_mode=20   1024x768  120Hz
hdmi_mode=21   1152x864  75Hz
hdmi_mode=22   1280x768        reduced blanking
hdmi_mode=23   1280x768  60Hz
hdmi_mode=24   1280x768  75Hz
hdmi_mode=25   1280x768  85Hz
hdmi_mode=26   1280x768  120Hz reduced blanking
hdmi_mode=27   1280x800        reduced blanking
hdmi_mode=28   1280x800  60Hz
hdmi_mode=29   1280x800  75Hz
hdmi_mode=30   1280x800  85Hz
hdmi_mode=31   1280x800  120Hz reduced blanking
hdmi_mode=32   1280x960  60Hz
hdmi_mode=33   1280x960  85Hz
hdmi_mode=34   1280x960  120Hz reduced blanking
hdmi_mode=35   1280x1024 60Hz
hdmi_mode=36   1280x1024 75Hz
hdmi_mode=37   1280x1024 85Hz
hdmi_mode=38   1280x1024 120Hz reduced blanking
hdmi_mode=39   1360x768  60Hz
hdmi_mode=40   1360x768  120Hz reduced blanking
hdmi_mode=41   1400x1050       reduced blanking
hdmi_mode=42   1400x1050 60Hz
hdmi_mode=43   1400x1050 75Hz
hdmi_mode=44   1400x1050 85Hz
hdmi_mode=45   1400x1050 120Hz reduced blanking
hdmi_mode=46   1440x900        reduced blanking
hdmi_mode=47   1440x900  60Hz
hdmi_mode=48   1440x900  75Hz
hdmi_mode=49   1440x900  85Hz
hdmi_mode=50   1440x900  120Hz reduced blanking
hdmi_mode=51   1600x1200 60Hz
hdmi_mode=52   1600x1200 65Hz
hdmi_mode=53   1600x1200 70Hz
hdmi_mode=54   1600x1200 75Hz
hdmi_mode=55   1600x1200 85Hz
hdmi_mode=56   1600x1200 120Hz reduced blanking
hdmi_mode=57   1680x1050       reduced blanking
hdmi_mode=58   1680x1050 60Hz
hdmi_mode=59   1680x1050 75Hz
hdmi_mode=60   1680x1050 85Hz
hdmi_mode=61   1680x1050 120Hz reduced blanking
hdmi_mode=62   1792x1344 60Hz
hdmi_mode=63   1792x1344 75Hz
hdmi_mode=64   1792x1344 120Hz reduced blanking
hdmi_mode=65   1856x1392 60Hz
hdmi_mode=66   1856x1392 75Hz
hdmi_mode=67   1856x1392 120Hz reduced blanking
hdmi_mode=68   1920x1200       reduced blanking
hdmi_mode=69   1920x1200 60Hz
hdmi_mode=70   1920x1200 75Hz
hdmi_mode=71   1920x1200 85Hz
hdmi_mode=72   1920x1200 120Hz reduced blanking
hdmi_mode=73   1920x1440 60Hz
hdmi_mode=74   1920x1440 75Hz
hdmi_mode=75   1920x1440 120Hz reduced blanking
hdmi_mode=76   2560x1600       reduced blanking
hdmi_mode=77   2560x1600 60Hz
hdmi_mode=78   2560x1600 75Hz
hdmi_mode=79   2560x1600 85Hz
hdmi_mode=80   2560x1600 120Hz reduced blanking
hdmi_mode=81   1366x768  60Hz
hdmi_mode=82   1080p     60Hz
hdmi_mode=83   1600x900        reduced blanking
hdmi_mode=84   2048x1152       reduced blanking
hdmi_mode=85   720p      60Hz
hdmi_mode=86   1366x768        reduced blanking

overscan_left

Number of pixels to skip on left.

overscan_right

Number of pixels to skip on right

overscan_top

Number of pixels to skip on top

overscan_bottom

Number of pixels to skip on bottom

framebuffer_width

Console framebuffer width in pixels. Default is display width minus overscan.

framebuffer_height

Console framebuffer height in pixels. Default is display height minus overscan.

framebuffer_depth

Console framebuffer depth in bits per pixel. Default is 16. 8bit is valid, but default RGB palette makes an unreadable screen. 24bit looks better but has corruption issues as of 20120615. 32bit has no corruption issues but needs framebuffer_ignore_alpha=1 and shows the wrong colors as of 20120615.

framebuffer_ignore_alpha

Set to 1 to disable alpha channel. Helps with 32bit.

test_mode

Enable test sound/image during boot for manufacturing test.

disable_l2cache

Disable arm access to GPU's L2 cache. Needs corresponding L2 disabled kernel. Default is 0.

disable_overscan

Set to 1 to disable overscan.

config_hdmi_boost

Configure the signal strength of the HDMI interface. Default is 2 on Pi 1 model B and 5 on later boards. Try increasing if you have interference issues with hdmi (e.g. to 7) 11 is the maximum.

TODO: Overclocking options