Mirrored Image and Capacitive Touch Nonresponsive

Hello, we are currently using the VAR-DT8MCustomBoard from Variscite with the Dart Mini. We have plugged in a customized 3.5 inch LVDS with a matching pinout according to the board datasheet.
The image loads on the screen after changing the size variable for the correct resolution, but there are two problems:

  1. the image is mirrored
    How do we get the image to be the correct orientation?
  2. the touch is nonresponsive
    The driver for the capacitive touch is FT5436. Is this driver not supported?

Still don’t know why the image is mirrored, but I think the reason the capacitive touch is not working is an incorrect resolution. How do you set the resolution for the CTP?

Hi @sarah-stephany,

It sounds to me like the driver is not included and would need to be configured once added. You can add their kernel module to test using these instructions: GitHub - balena-os/kernel-module-build: Example project for building an OOT kernel module in balena. If that solves the issue for you, you can submit a PR to have the driver added to the Dart Mini device-type (so that it isn’t wiped away during reboot like it will with the testing process I shared).

Since the screen is LVDS it is using the bridge that is included in the blob. The capacitive driver (FT5436) is also included in the blob as FT54x06 but the resolution is incorrect at 800x480… see below.


  • Would I need to specifically add the TFT driver (ILI9488) when it is using a bridge?
  • Will changing the blob to the correct sizing be an appropriate fix?
  • Is there a variable or Chromium command that will allow me to rotate the screen and un-mirror the display?

i2c@30a20000 {
compatible = “fsl,imx8mm-i2c\0fsl,imx21-i2c”;
#address-cells = <0x01>;
#size-cells = <0x00>;
reg = <0x30a20000 0x10000>;
interrupts = <0x00 0x23 0x04>;
clocks = <0x02 0xa4>;
status = “okay”;
clock-frequency = <0x186a0>;
pinctrl-names = “default\0gpio”;
pinctrl-0 = <0x2a>;
pinctrl-1 = <0x2b>;
scl-gpios = <0x22 0x0e 0x00>;
sda-gpios = <0x22 0x0f 0x00>;

			sn65dsi84@2c {
				compatible = "ti,sn65dsi83";
				reg = <0x2c>;
				ti,dsi-lanes = <0x04>;
				ti,lvds-format = <0x01>;
				ti,lvds-bpp = <0x18>;
				ti,lvds-channels = <0x01>;
				ti,width-mm = <0x9a>;
				ti,height-mm = <0x57>;
				enable-gpios = <0x2c 0x0b 0x00>;
				pinctrl-names = "default";
				pinctrl-0 = <0x2d>;
				status = "okay";

				display-timings {

					lvds {
						clock-frequency = <0x1f78a40>;
						hactive = <0x320>;
						vactive = <0x1e0>;
						hback-porch = <0x28>;
						hfront-porch = <0x28>;
						vback-porch = <0x1d>;
						vfront-porch = <0x0d>;
						hsync-len = <0x30>;
						vsync-len = <0x03>;
						hsync-active = <0x00>;
						vsync-active = <0x00>;
						de-active = <0x01>;
						pixelclk-active = <0x00>;

		i2c@30a30000 {
			compatible = "fsl,imx8mm-i2c\0fsl,imx21-i2c";
			#address-cells = <0x01>;
			#size-cells = <0x00>;
			reg = <0x30a30000 0x10000>;
			interrupts = <0x00 0x24 0x04>;
			clocks = <0x02 0xa5>;
			status = "okay";
			clock-frequency = <0x186a0>;
			pinctrl-names = "default\0gpio";
			pinctrl-0 = <0x30>;
			pinctrl-1 = <0x31>;
			scl-gpios = <0x22 0x10 0x00>;
			sda-gpios = <0x22 0x11 0x00>;

			ft5x06_ts@38 {
				status = "okay";
				compatible = "edt,edt-ft5206";
				reg = <0x38>;
				pinctrl-names = "default";
				pinctrl-0 = <0x32>;
				reset-gpios = <0x33 0x04 0x01>;
				interrupt-parent = <0x23>;
				interrupts = <0x0e 0x02>;
				touchscreen-size-x = <0x320>;
				touchscreen-size-y = <0x1e0>;

@the-real-kenna I was able to change the .dtb by accessing it in /mnt/sysroot/active/current/boot so the sizing issue has been fixed.

I still cannot fix the mirrored problem as the words are still backwards on the screen. Any ideas on how to change this?

  1. To correct the image orientation, you can try adjusting the display settings in your operating system or graphics driver. Look for options related to screen rotation or display orientation and experiment with different settings until the image appears correctly.

  2. If the touch functionality is not working, ensure that the touch cable is securely connected. Additionally, verify if the correct touch driver is installed for the FT5436 capacitive touch controller. You may need to search for and install the appropriate driver specific to your operating system.