Enable RNDIS USB Device in Torizon 7.x.x

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Hello! Thank you for your detailed description. Let’s address your questions and get USB device mode working on Torizon 7.x.x.

1. Permission Issue with echo and sudo

This is a common shell issue: sudo only elevates echo, not the redirection (>). The file write is still done as the regular user. To resolve, use sudo with sh -c like this:

sudo sh -c 'echo 0x1b67 > idVendor'

Apply this pattern for all echo commands writing to files under /sys.

You can also run a root shell with sudo -i or, in your script/service, ensure the whole process runs as root.

More details:
USB Device Mode (Linux) | Toradex Developer Center

2. USB Host Power Regulator and Device Functionality

Disabling the host VBUS regulator (&reg_usb_host_vbus) should not affect USB device mode; host and device use separate controllers. This device tree change only disables power switching for host mode, so it does not interfere with gadget/device operation.

3. Device Tree Branch

For Torizon OS 7.1.0, make sure you use the device tree based on branch toradex_6.6-2.2.x-imx for i.MX6. See more:
Add Device Tree Branch to Release Matrix

4. Gadget Not Starting

If the gadget is configured but not starting, ensure:

  • ConfigFS is mounted at /sys/kernel/config

  • All necessary function drivers (e.g., usb_f_mass_storage, usb_f_ecm, etc.) are loaded

  • udc is properly set: after creating and configuring, make sure you assign the UDC:

    sudo sh -c 'echo <udc_name> > UDC'

    where <udc_name> is typically found by listing /sys/class/udc/ (e.g., ci_hdrc.0).

  • Check for kernel logs (dmesg) for USB or gadget-related issues.

5. General Setup Steps

Here is a simplified sequence, run as root or with each command wrapped in sudo sh -c:

mount -t configfs none /sys/kernel/config
cd /sys/kernel/config/usb_gadget/
mkdir -p g2
cd g2

echo 0x1b67 > idVendor
echo 0x4000 > idProduct

mkdir -p strings/0x409
echo "1234567890" > strings/0x409/serialnumber
echo "Toradex" > strings/0x409/manufacturer
echo "USB Gadget" > strings/0x409/product

mkdir -p configs/c.1/strings/0x409
echo "Config 1: ECM network" > configs/c.1/strings/0x409/configuration

mkdir -p functions/ecm.usb0
ln -s functions/ecm.usb0 configs/c.1/

ls /sys/class/udc  # outputs something like 'ci_hdrc.0'
echo ci_hdrc.0 > UDC

See USB Device Mode (Linux) for more examples and explanation.

If after these steps the device is still not enumerating, let me know the dmesg output after configuring the gadget, and the result of lsusb on the host.

Best regards, Toradex AI Assistant.