config.txt

# Default Nerves RPi 4 config.txt
#
# It's possible to override this file by using a custom fwup.conf
# configuration to pull in a replacement.
#
# Useful links:
# http://rpf.io/configtxt
# https://www.raspberrypi.org/documentation/configuration/device-tree.md
# https://github.com/raspberrypi/documentation/blob/master/configuration/device-tree.md
# https://github.com/raspberrypi/firmware/blob/master/boot/overlays/README

# Enable 64-bit support
arm_64bit=1

# We always use the same names. The variant is selected in fwup.conf.
start_file=start4.elf
fixup_file=fixup4.dat

# Max for cm4
over_voltage=6
#uncomment to overclock the arm. 700 MHz is the default.
arm_freq=2147
gpu_freq=750

#arm_boost (Raspberry Pi 4 Only)
arm_boost=1 

# Don't have the firmware create an initial video= setting in cmdline.txt.
# Use the kernel's default instead.
#disable_fw_kms_setup=1

# Disable compensation for displays with overscan
disable_overscan=1

#hdmi_enable_4kp60=1

# Enable I2C and SPI
dtparam=i2c_arm=on
dtparam=spi=on

# Enable the UART (/dev/ttyS0)
enable_uart=1

# Automatically load overlays for detected DSI displays
display_auto_detect=1

# Switch to external antenna.
dtparam=ant2

# Disable the boot rainbow
disable_splash=1

#By default, the Raspberry Pi Touch Display is used when detected on the I2C bus
ignore_lcd=1
#lcd_rotate=2
#display_lcd_rotate=1

# For the CM4 I/O board, USB is disabled by default. This enables it.
dtoverlay=dwc2,dr_mode=host

# This, along with the Raspberry Pi "x" firmware is needed for the camera
# to work. The Raspberry Pi "x" firmware is selected via the Buildroot
# configuration. See Target packages->Hardware handling->Firmware.
gpu_mem=512

# Enable DRM VC4 V3D driver
dtoverlay=vc4-kms-v3d-pi4,cma-512
max_framebuffers=2

dtoverlay=i2c1,pins_2_3
dtoverlay=i2c3,pins_4_5
dtparam=i2c1=on
dtparam=i2c3=on

# The ramoops overlay works with the pstore driver to preserve crash
# information across reboots in DRAM
dtoverlay=ramoops

gpio=13=pu
dtoverlay=reTerminal,tp_rotate=1