ARK Just A Jetson Modalix Bundle

ARK Just A Jetson carrier, SiMa.ai Modalix SOM, heatsink and fan. Optional NDAA 480GB M.2 NVMe SSD.

The carrier is the same hardware as ARK Just A Jetson. This page covers SOM differences only.

The ARK carrier is NDAA. The SOM is SiMa.ai.

Carrier Hardware

ARK Just A Jetson

Use the JAJ Hardware Reference for pinout, power, and 3D models. Do not use the JAJ Flashing Guide or USB-C Console gadget login.

Where to Start

Do not use NVIDIA SDK Manager or L4T. The SOM boots from built-in eMMC; an NVMe SSD is not required.

1. Apply the ARK carrier overlay to the running eLxr image — ark-meta-simaai. The overlay ships as a versioned release package:

   curl -LO https://raw.githubusercontent.com/ARK-Electronics/ark-meta-simaai/main/packaging/provision_from_package.sh
   chmod +x provision_from_package.sh
   BOARD=sima@<ip> ./provision_from_package.sh jaj

   cat /etc/ark_modalix afterwards reports which overlay release the board carries.

2. Install the ARK-OS modalix package — see ARK-OS.

3. ML tooling — SiMa.ai Palette and SiMa.ai hardware docs.

SiMa eLxr default login: user sima, password edgeai, hostname modalix. ARK-OS services run as sima.

Interface Differences

Interface	Modalix
UART2	Works as a console
CAN	No CAN interface
HDMI	Works only if the Modalix SOM was ordered with the HDMI option. ARK units will not have HDMI.
PCIE2	Only works when HDMI is not used. On ARK units (no HDMI), PCIE2 is available
M.2 Key E	No PCIE
USB-C	USB 3.0 works as a host. USB 2.0 on that connector goes to an FTDI console on the SOM (not Jetson gadget device mode)
UART0	Works without flow control (no RTS/CTS)
UART1	Does not work
Ethernet	Carrier gigabit Ethernet works on stock eLxr, before the ARK overlay is applied

Do not install the Jetson Wi-Fi 6E / Remote ID M.2 option — M.2 Key E has no PCIE on Modalix.

The JAJ Ports and Serial UART map (/dev/ttyTHS*) is for NVIDIA Jetson modules.

Console

UART2 is the console. USB-C USB 2.0 is an FTDI console on the SOM. USB-C USB 3.0 is host only.

Do not use the Jetson USB-C gadget login (jetson / 192.168.55.1). The SOM has no USB device controller at all (/sys/class/udc is empty), so no USB gadget networking of any kind is available — this is not just a different gadget address.

Recovery

If the eMMC image is unbootable, reflash eLxr with SiMa's netboot path — ./flash.sh JAJ --netboot in ark-meta-simaai, which drives sima-cli over TFTP. There is no NVIDIA Force Recovery mode on this SOM.

Storage

Boots from on-module eMMC. M.2 Key M NVMe is optional extra storage.

Display / PCIe

ARK-sold Modalix SOMs do not include HDMI. Because HDMI is unused, PCIE2 is available.

M.2 Key M is still NVMe. M.2 Key E has no PCIE.

ARK-OS

ARK-OS is a Debian package, not a full OS image. Flash eLxr first, then install the modalix platform on the board (user sima must exist):

curl -fSLO https://github.com/ARK-Electronics/ARK-OS/releases/download/v1.3.0/ark-os-modalix-bookworm_1.3.0_arm64.deb
sudo apt-get install -y ./ark-os-modalix-bookworm_1.3.0_arm64.deb

Use apt-get install, not dpkg -i — the package has dependencies (nginx, gstreamer) that only apt resolves.

The package is named bookworm while eLxr 12 reports its own codename, aria. They are ABI-compatible; the bookworm build is the one to install. If you use packaging/install_ark_os.sh instead, pass --codename=bookworm, or it will look for an aria asset that is not published.

Do not install the jetson package.

ARK-UI is at http://modalix.local (or the board's IP). Do not use jetson.local or USB-C gadget networking.

Compared with ARK-OS on Jetson:

• No jtop / jetson-stats

• No jetson-can (no SOM CAN)

• No rid-transmitter

• FMU reset / VBUS GPIO helpers are no-ops until mapped

• mavlink-router still uses the USB flight-controller path when an FC is on USB

ARK-OS

Performance

Vendor peak ratings, not a lab benchmark:

Module	Peak TOPS	Rated power
SiMa.ai Modalix	50 TOPS (BF16/INT8/INT16)	sub-10W
NVIDIA Jetson Orin Nano 8GB	40 TOPS; Super 67 TOPS	25W
NVIDIA Jetson Orin NX 16GB	100 TOPS; Super 157 TOPS	40W

Modalix has higher TOPS per watt than Orin Nano Super and Orin NX Super at those rated points. Peak TOPS on Super NX is higher.

External

• SiMa.ai MLSoC Family

• SiMa.ai Developer Center (Palette)

• SiMa.ai Hardware Docs

• ark-meta-simaai — ARK carrier device tree and flash tooling

• ARK-OS — modalix platform package