Showing changes from revision #7 to #8:
Added | Removed | Changed
The Raspberry Pi boot loader uses the config.txt
file to hold configuration parameters relevant at boot time. It is a plain text file, resident in the DOS partition of the boot SD card, alongside RISCOS.IMG etc. (for more information on other files in the DOS partition, see Software information: Raspberry Pi: Firmware)
It should not be confused with cmdline.txt (which is used to pass parameters to RISC OS at boot time).
The suggested contents of config.txt are as follows:
[pi4]
enable_gic=1
[all]
fake_vsync_isr=1
framebuffer_swap=0
gpu_mem=64
init_emmc_clock=100000000
ramfsfile=CMOS
ramfsaddr=0x508000
kernel=RISCOS.IMG
Note that the list is split1 into two parts: the “pi4” section contains parameters for the Pi 4 only, while the “all” section contains parameters applicable to all versions of Raspberry Pi (including the Pi 4). Within each section, parameters can appear in any order: the important thing is to make sure they are in the right section!
1 The technique of splitting the list into multiple sections is explained in detail on the Conditional filters page at the Raspberry Pi website.
The entries on the list have the following meanings:
enable_gic=1
fake_vsync_isr=1
framebuffer_swap=0
gpu_mem=64
init_emmc_clock=100000000
ramfsfile=CMOS
ramfsaddr=0x508000
kernel=RISCOS.IMG
The following two entries are useful if you want to use the 3.5mm audio output jack instead of via the HDMI cable.
hdmi_ignore_edid_audio=1
audio_pwm_mode=2
These parameters are used to specify the monitor’s native pixel resolution. You might use them if you are using the AnyMode utility, if your monitor does not support EDID, or if you want the Pi to run “headless” (i.e. without a monitor attached, and with all communication via VNC or similar).
Monitor type | hdmi_group | hdmi_mode | Notes |
---|---|---|---|
1 | 16 | ||
1 | 31 | ||
2 | 39 | ||
2 | 58 | ||
2 | 69 | ||
2 | 82 |
For example, to specify a screen size of 1920×1080, you would use:
hdmi_group=2
hdmi_mode=82
If your monitor size is not listed above, see this documentation page on the Raspberry Pi website for other hdmi_mode and hdmi_group values.
hdmi_blanking=1
hdmi_enable_4kp60=1
hdmi_force_hotplug=1
disable_overscan
max_framebuffer_width, max_framebuffer_height, hdmi_pixel_freq_limit
sdtv_mode=2
2 Putting it in the “pi4” section isn’t strictly necessary (as older models of Raspberry Pi will ignore it) but it does make it clear it is for the Pi 4 only.
The following entries may also be useful in certain circumstances:
boot_delay
bootcode_delay