JohnnyMnemonic

Thanks, @gprovost, that does appear to be the case. I'm not sure why that is, though. I'm fairly certain I'm using a USB 3.0 port on my Debian PC. I plugged an external HDD into the same port and I think it gets recognized as a USB 3.0 port (I'm guessing because of the 5000M: XXXXX@deadshot:~ $ lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M |__ Port 6: Dev 3, If 0, Class=Mass Storage, Driver=usb-storage, 5000M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M When I plug my Helio64 into the same port on my Debian PC, using the included USB Type-C to USB-A cable, it doesn't show as a Mass Storage device: XXXXX@deadshot:~ $ lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M |__ Port 10: Dev 7, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M EDIT: Not sure what I did, but it suddenly started working: XXXXX@deadshot:~ $ lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M |__ Port 3: Dev 7, If 0, Class=Mass Storage, Driver=usb-storage, 5000M |__ Port 5: Dev 6, If 0, Class=Mass Storage, Driver=usb-storage, 5000M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M |__ Port 3: Dev 10, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M I see both the FTDI and the Mass Storage device (the other is another external drive I have). I guess I won't look a gift horse in the mouth and be glad that it's working!

Thanks @Zageron, my account's been "activated"! Kobol folks, if it helps, I see the following when plugging/unplugging the USB cable onto a Debian PC: XXXXX@deadshot:~ $ lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M |__ Port 5: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M XXXXX@deadshot:~ $ lsusb -t /: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/6p, 5000M |__ Port 5: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M /: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/8p, 480M /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/15p, 480M |__ Port 2: Dev 26, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/3p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/6p, 480M Seems that Helios64 gets picked up as this: Port 2: Dev 26, If 0, Class=Vendor Specific Class, Driver=ftdi_sio, 12M with the following line via lsusb (without the -t flag): Bus 002 Device 025: ID 0403:6015 Future Technology Devices International, Ltd Bridge(I2C/SPI/UART/FIFO)

Thanks for the quick response, @aprayoga! I gave it a shot and unfortunately it doesn't seem to work for me. I've upgraded to Armbian 20.11, which includes LK 5.9: XXXXX@helios64:~ $ uname -r 5.9.10-rockchip64 XXXXX@helios64:~ $ cat /etc/os-release PRETTY_NAME="Armbian 20.11 Buster" NAME="Debian GNU/Linux" VERSION_ID="10" VERSION="10 (buster)" VERSION_CODENAME=buster ID=debian HOME_URL="https://www.debian.org/" SUPPORT_URL="https://www.debian.org/support" BUG_REPORT_URL="https://bugs.debian.org/" I've created that file and applied the user overlay as suggested: XXXXX@helios64:/etc $ cat dwc3-0-device.dts /dts-v1/; /plugin/; / { compatible = "rockchip,rk3399"; fragment@0 { target = <&usbdrd_dwc3_0>; __overlay__ { dr_mode = "peripheral"; }; }; }; XXXXX@helios64:/etc $ sudo armbian-add-overlay dwc3-0-device.dts Compiling the overlay Copying the compiled overlay file to /boot/overlay-user/ Overlay dwc3-0-device was already added to /boot/armbianEnv.txt, skipping Reboot is required to apply the changes XXXXX@helios64:/etc $ sudo reboot And then after the reboot: XXXXX@helios64:~ $ sudo modprobe g_mass_storage file=/dev/sda,/dev/sdb,/dev/sdd iSerialNumber=1234567890 iManufacturer="Kobol Innovations" iProduct=Helios64 I see the following in /var/log/syslog: Nov 27 15:26:36 localhost kernel: [ 3714.194647] Mass Storage Function, version: 2009/09/11 Nov 27 15:26:36 localhost kernel: [ 3714.194664] LUN: removable file: (no medium) Nov 27 15:26:36 localhost kernel: [ 3714.194866] LUN: file: /dev/sda Nov 27 15:26:36 localhost kernel: [ 3714.194973] LUN: file: /dev/sdb Nov 27 15:26:36 localhost kernel: [ 3714.195075] LUN: file: /dev/sdd Nov 27 15:26:36 localhost kernel: [ 3714.195083] Number of LUNs=3 Nov 27 15:26:36 localhost kernel: [ 3714.195344] g_mass_storage gadget: Mass Storage Gadget, version: 2009/09/11 Nov 27 15:26:36 localhost kernel: [ 3714.195354] g_mass_storage gadget: g_mass_storage ready I've tried with both a Windows PC and a Linux (Debian) PC, with no luck. I can try and provide anything else needed to troubleshoot, though it may take some time as I'm limited to just one post per day. Thanks!

Does enabling this user overlay to allow DAS mode on LK 5.9 disable the ability to use USB-C for a terminal (as described here: https://wiki.kobol.io/helios64/install/first-start/)?