Setting Custom Resolution on Raspberry Pi to Fit 1:1 Display

I have a Raspberry Pi connected to a 480x480 circular touch screen. I have edited the config.txt to reflect the new resolution I want to run. Unfortunately the resolution is only displayed correctly using VNC on the display itself it is weirdly offset and not at all in a 1:1 Aspect ratio.

Touch works like a charm. I already searched Google for how to set the aspect ratio correctly etc. Any ideas what I could try?

config.txt:

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
# hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
# disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
# overscan_left=16
# overscan_right=16
# overscan_top=16
# overscan_bottom=16

# uncomment to force a console size. By default it will be display's size minus
# overscan.
# framebuffer_width=480
# framebuffer_height=480

# uncomment if hdmi display is not detected and composite is being output
hdmi_force_hotplug=1
hdmi_cvt=480 480 60 4 

# uncomment to force a specific HDMI mode (this will force VGA)
hdmi_group=2
hdmi_mode=87

# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_=drive

# uncomment to increase signal to HDMI, if you have interference, blanking, or
# no display
#config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable infrared communication.
#dtoverlay=gpio-ir,gpio_pin=17
#dtoverlay=gpio-ir-tx,gpio_pin=18

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

[all]
#dtoverlay=vc4-fkms-v3d

Solution

I ended up contacting the AliExpress Seller who contacted the manufacturer. They sent me this config with custom HDMI timings. There is also a commented line for 720x720px

# For more options and information see
# http://rpf.io/configtxt
# Some settings may impact device functionality. See link above for details

# uncomment if you get no picture on HDMI for a default "safe" mode
#hdmi_safe=1

# uncomment this if your display has a black border of unused pixels visible
# and your display can output without overscan
#disable_overscan=1

# uncomment the following to adjust overscan. Use positive numbers if console
# goes off screen, and negative if there is too much border
#overscan_left=8
#overscan_right=1
overscan_top=0
overscan_bottom=0






# uncomment to force a console size. By default it will be display's size minus
# overscan.
framebuffer_width=480
framebuffer_height=480
hdmi_group=2
hdmi_mode=87

#framebuffer_width=1920
#framebuffer_height=1080

hdmi_timings=480 1 10 20 50 480 1 10 10 5 0 0 0 60 0 16960000 4
#hdmi_timings=720 1 20 20 40 720 1 10 10 5 0 0 0 65 0 39000000 4

#hdmi_timings=1080 1 26 2 36 1920 1 8 4 16 0 0 0 62 0 138167744 3


#max_framebuffer_width=1920
#max_framebuffer_height=1080
#hdmi_pixel_freq_limit=400000000

max_framebuffer_width=480
max_framebuffer_height=480
hdmi_pixel_freq_limit=400000000

# uncomment if hdmi display is not detected and composite is being output
#hdmi_force_hotplug=1

# uncomment to force a specific HDMI mode (this will force VGA)
#hdmi_group=1
#hdmi_mode=1

#hdmi_group=2
#hdmi_mode=87


# uncomment to force a HDMI mode rather than DVI. This can make audio work in
# DMT (computer monitor) modes
#hdmi_drive=2
#hdmi_drive=1


# uncomment to increase signal to HDMI, if you have interference, blanking, or
no display
# config_hdmi_boost=4

# uncomment for composite PAL
#sdtv_mode=2

#uncomment to overclock the arm. 700 MHz is the default.
#arm_freq=800

# Uncomment some or all of these to enable the optional hardware interfaces
#dtparam=i2c_arm=on
#dtparam=i2s=on
#dtparam=spi=on

# Uncomment this to enable the lirc-rpi module
#dtoverlay=lirc-rpi

# Additional overlays and parameters are documented /boot/overlays/README

# Enable audio (loads snd_bcm2835)
dtparam=audio=on
display_hdmi_rotate=0

Now it works