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ROC-RK3399-PC (Renegade Elite) Crowdfunding Begins

Renegade Elite is the first mass-market SBC built specifically to tackle modern applications in artificial intelligence, stereo computer vision, neural-networks, robotics, and general purpose GPU compute. It also revolutionizes traditional markets like digital signage, high density micro-server, and connected edge devices at its $99 price point. All of this is enabled by a device slightly longer than a 2.5″ drive.

Together with revolutionary standards-compliant technologies like USB Type-C and Power-over-Ethernet, Renegade Elite offers what no other competitor can match.

Find out more @Indiegogo.

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Renegade Elite: Indiegogo Campaign Launch

The ROC-RK3399-PC (Renegade Elite) is the culmination of six months of development effort between the Libre Computer Project and Firefly teams to re-envision computing as we know it. We have analyzed almost all usage scenarios for the edge computing market to derive a design that enables usability of core high-performance features of the Rockchip RK3399 System-on-Chip.

Find out more on Indiegogo.


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Raspbian (Stretch) Desktop for ALL-H3-CC H5 2GB 64-bit Variant (Tritium) Preview Image 1

Announcing our first image for ALL-H3-CC (Tritium) H5 2GB 64-bit boards based on Linux 4.18rc3. We originally planned to release images for the H3 and H2+ variants as well but there’s some bugs that still need to be ironed out with the Linux 4.18rc kernel.

Like the Raspbian image for AML-S905X-CC (Le Potato) released yesterday, this image features a 64-bit kernel running 32-bit Raspbian user space. It has the same limitations as well. Give it a go and let us know!

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Raspbian (Stretch) Desktop for AML-S905X-CC (Le Potato) Preview Image 1

Raspbian is a highly optimized Debian-derived Linux-based distro made for Raspberry Pi boards. It supports all of Raspberry Pi’s products going back to the very first Raspberry Pi from 2012. The BCM2835 found on that first board is based on ARMv6 technology so it cannot run Debian ports or Ubuntu ports compiled for ARMv7 or ARMv8 (64-bit). Thus Raspbian was created from Debian packages compiled to target ARMv6 with VFPv2 instead of VFPv3+ and NEON float point support found in ARMv7+.

The Raspberry Pi Foundation and the community maintains this light operating system and suited it with a bundle of utilities for the education market including Scratch, Mathematica, Wolfram, and more. The custom desktop UI uses LXDE which uses very little RAM and processing power compared to traditional PC desktop environments like Gnome and KDE. This allows students, educators, and other people without Linux terminal knowledge to use the devices in a format that they are accustomed to.

Because Debian is FOSS and community-driven, it is very easy to run Raspbian on top of other hardware. We have mated our Linux 4.14 LTS kernel and bootloader for AML-S905X-CC to Raspbian. If you are coming from a Raspberry Pi board, this image should provide the same intuitiveness and tools that you are familiar with. There were two improvements made: automatic swap partition creation and localization to US English.

The kernel is compiled as 64-bit ARMv8 and running the 32-bit ARMv6 Raspbian user-space. This means that the full performance benefits of 64-bit ARMv8 architecture will not be in the native applications but you get significant in-kernel improvements. Raspbian also doesn’t support multiarch so it is not simple to run 64-bit ARMv8 applications with this image. This also prevents 3D acceleration by the GPU although the LXDE desktop environment is plenty fast without it.

We will spin our own fully 64-bit Ubuntu image based on LXDE as well in the near future. Look forward to a full suite of Tritium images including Raspbian in another week as Linux 4.18 stabilizes.

You can grab this image from the AML-S905X-CC product page under Downloads. There’s also a Google Drive share link in the README.txt. Please give it a spin and let us know what you think. Have a wonderful July 4th!

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AML-S805X-AC (La-Frite) Announcement, Ubuntu 18.04 (Bionic Beaver) LTS for AML-S905X-CC (Le Potato) Preview Image 3, Raspbian, and Upstream Software Roadmap

Since we started our endeavor, we have made tremendous progress on the software side of the AML-S905X-CC (Le Potato) platform through our collaboration with BayLibre. We are happy to announce that the platform will be getting a mini-me, the AML-S805X-AC (La Frite). This smaller and more cost-oriented board shares the same underlying technology as its bigger brother and will utilize the upstream work completed so far. It is limited to 1080P instead of 4K60 like Le Potato. The crowdfunding will occur at the end of July after we release the images for ALL-H3-CC series (Tritium). This will coincide with the Indiegogo campaign for ROC-RK3399-PC (Renegade Elite). More details to come about both of these projects.

Meanwhile, we have released a new preview image for the current AML-S905X-CC. This image fixes two outstanding issues:

  • floating MAC address causing new DHCP IP leases
  • support for automatically generating timings for DMT resolutions

The images slipstreams the latest Linux 4.14.52. If you already have preview image 2, this is not much of an upgrade.

We have been quietly working on support for Raspbian. The work is relatively simple and we have been testing it internally for release in the next 10 days. It will come in two forms: an image and a script to install on top of existing Raspbian for Raspberry Pi. This will work for both Le Potato and Tritium platforms.

LXDE is much faster than Gnome 3 on these low power ARM hardware. It is the basis for the latest desktop UI for Raspbian. We will start rolling Ubuntu with LXDE on X11 along side the Gnome 3 with Wayland images for usability reasons.

Upstream roadmap items being worked on include the following:

  • 4K30 support in Linux (4K60 requires a lot of work still)
  • single resolution video output and framebuffer in u-boot
  • SPI-FC support for AML-S805X-AC in u-boot
  • DRM overlays in Linux
  • Device tree overlays (like HAT support in Raspbian for Raspberry Pi boards)

Logistical roadmap items being worked on include the following:

  • Unified kernel for ALL-H3-CC H5, AML-S905X-CC, ROC-RK3328-CC based on Linux 4.18
  • Debian repo infrastructure and packaging for kernel and u-boot for all of our boards
  • Continuous integration and image buildbot
  • European distribution

These two lists are not comprehensive. It will be a fun summer with lots to do.

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Determining Boot Duration Issues on Our Ubuntu 18.04 (Bionic Beaver) Preview Images for AML-S905X-CC (Le Potato)

One of the major issues with our previous Ubuntu 18.04 preview release images was the long 5 minute boot time. We did a little debugging on that front to find out the exact reason and to derive a resolution. In this article we go over the steps that we took to help people understand how to approach similar issues. Please note that the problem is not related or relevant for official Ubuntu images for x86 and Armbian Ubuntu 18.04 images.


To start off with a background of the boot process for our images, we have to begin with the disk layout for our Ubuntu images. Our images are released as a zip file of the raw block data. The raw image is 4GB in size using a MBR partition system composed of two primary partitions.

Disk Image (4GB):

  • MBR Partition System (512 Byte Sectors)
    • Empty Space – Sector 0 to 2047 (0MB to 1MB) – MBR and u-boot
    • Partition 1 – Sector 2048 to 524287 (1MB to 256MB) – FAT (EFI) – /boot
    • Partition 2 – Sector 524288 to 8191999 (256MB to End) – btrfs

When you flash this image onto a MicroSD card using dd or Win32DiskImager, you only have to flash 4GB even if the MicroSD card is much larger. Upon boot, the image has a run-once script, lc_repart_disk_once, that determines the actual MicroSD card size and re-formats the disk to make use of the empty space > 4GB.

It computes the last incomplete gigabyte (1024 ^ 3) and creates primary partition 3 in that space for a swap partition. Then it extends primary partition 2 to use all of the intermediary space. BTRFS can be resized online so there no need to reboot to extend it. The swap partition is added to /etc/fstab and turned on.


Since most of the early kernel actions happen when there isn’t a GUI, we used our trusty UART to USB adapter to get early access to the system. We connected it to the three pin 2J1 connector which is highlighted in red on the picture below.

AML-S905X-CC UART 2J1 Connector
2J1 Connector Highlighted in Red: Ground (BLACK) TX (WHITE) RX (GREEN)

We use Ubuntu/Debian internally so we ran sudo minicom -b 115200 -D /dev/ttyUSB0 on our computers after plugging in the UART cable. The baud rate for the board is set to 115200 in software. We had to disable the hardware flow control by pressing Control+A, O, Serial port setup, F.

Problem Isolation and Resolution

Ubuntu 18.04 like Ubuntu 16.04 before it uses systemd as the init system which allows for clear dependencies and parallel process execution. There are two valuable tools: journalctl for reading logs and systemd-analyze for determining the process tree that took the longest.

It takes about 20 seconds for the board to get to UART TTY prompt. We login using libre and computer as the username and password respectively. We crawled through the boot logs using sudo journalctl to find that lc_repart_disk_once was timing out after 5 minutes and getting restarted. The other way to determine this was by running sudo systemd-analyze criticial-chain. After a system is fully booted (or timed out), this will give you the process tree that took the longest time with each process itemized.

Next, we enabled debugging on the lc_repart_disk_once shell script by adding set -x to enable verbose output that can be examined via sudo journalctl -u lc_repart_disk_once. We noticed that the mkswap command in the script seems to hang for a few minutes even though it should only take a few seconds.

To trace what goes wrong with a process, we installed the handy strace utility via sudo apt-get install strace. This utility will report userspace and kernel interactions. By prefixing the mkswap command with strace a script, we were able to determine exactly what mkswap was doing.

After restoring the filesystem to its original state, we restarted the system. sudo journalctl -u lc_repart_disk_once reported that mkswap was hanging on a read from /dev/random which is a system entropy issue. The annoying thing with /dev/random is that reading from it is a blocking call when system entropy gets low and won’t unblock until system entropy recovers, which can be quite slow. We checked sudo cat /proc/sys/kernel/random/entropy_avail and sure enough it was below 100, which will cause reads from /dev/random to block.

Luckily, the Amlogic S905X found in Le Potato has a built-in hardware random number generator (RNG) and BayLibre upstreamed support for it in Linux 4.8. All that was missing is the rng-tools daemon that will back the /dev/random with the HWRNG in /dev/hwrng. By installing it via sudo apt-get install rng-tools, we were able to let mkswap finish within seconds instead of hanging on entropy.

This problem is not readily transparent or an issue with the application code. It is sometimes critical for an user or developer to understand how Linux (and system level design) works in order to develop an effective solution and not resort to workarounds like patching base utilities or working around system level problems in application level logic.


With this all being said and done, we have released our Ubuntu 18.04 Preview Image 3 which now boots in two minutes to the Gnome Display Manager instead of five minutes on the first run. Second boots takes less than 45 seconds. The headless boot times have not changed from the previous 20 seconds. This is a tremendous improvement to usability.

Other Thoughts

We have started putting images in Google Drive for faster downloads. You can find them in the README.txt. Other changes in PI3 include Linux LTS 4.14.50, defaulting to Wayland in GDM for the libre user, increased compressed memory pool, and a few more resolutions. Outstanding issues include overlay implementation, upstream Linux support for 2K/4K HDMI output, and VPU work for accelerated video decoding. Ely, a community member, has contributed work towards open source hardware video decoding which is very exciting.

We expect another preview release before we have a formal release. We are currently getting infrastructure in place to host repositories for the formal release so you can sudo apt-get update && sudo apt-get upgrade to keep everything up to date instead of re-flashing MicroSD cards.

By the time the next Linux LTS rolls around (4.19 in October), we should have an unified image for all three of the current CC and CM platforms.

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Ubuntu 18.04 (Bionic Beaver) LTS for AML-S905X-CC (Le Potato) Preview Image 2

This is a quick update to the previous preview release 1 with a newer 4.14.49 kernel.

We fixed the USB/mali conflict and the USB ports will not hang if something is plugged into the OTG port while mali is enabled.

The reason for the long boot process is due mkswap taking what seems like forever on 18.04. We have not isolated the cause yet so we will continue to address that issue as well as many other kernel side features.

We will be creating a linux flashing utility to this platform for eMMC much akin to the fel-mass-storage utility for Allwinner boards. You will be able to directly flash SD, eMMC, and NOR via a Type A to Type A cable that is included with our eMMC modules.

Le Potato will be getting a little brother soon…

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GPIO Headers Reference for AML-S905X-CC

GPIOs (General Purpose Input/Output) are single-bit pins capable of digital input or output typically used for controlling LEDs or signaling. There is a total of 35 GPIO pins operating at 3.3V logic level on Le Potato which is 7 more than what is found on the Raspberry Pi series of boards. GPIOs are half duplex which means they can only be in either input or output mode but not both simultaneously.

When setup for input, applying 3.3V or 0V to the pin will correspond to 1 or 0 respectively when read in software. When setup for output, the pins will be either 3.3V or 0V depending on whether it is set as 1 or 0 in software. GPIOs typically provide only a few milli-amps of current so they should only directly drive low power things like LEDs. They cannot drive power hungry things like DC motors, which need power transistors to deliver adequate current.

Some of the GPIO pins have secondary functionality for signaling SPDIF, I2S, I2C, SPI, SDIO, UART, PCM, clock-generation, and more. They still operate at the same 3.3V logic level but these pins are usually connected to internal specialized hardware that can generate precisely timed signals without using the CPU to bit bang. This frees up the CPU to do other things like running your operating system and software.

There are two interfaces in the Linux kernel for controlling and reading from GPIO pins. Since the interfaces are standardized, you do not need to use libraries to read from and write to GPIOs. We have put together a simple guide for utilizing these interfaces. As an addition, we also mapped out the functionality and software pin numbers on Le Potato for easy access.

Screenshot from 2018-05-21 11-48-00

On the picture at the top of the page, GPIOs on the Le Potato are highlighted in green. 5V pins are red, 3.3V pins are orange, ADC pins are blue. Other un-highlighted pins are ground with the exception of the pins on the top right header.

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Comprehensive Documentation for ROC-RK3328-CC by Firefly Team

ROC-RK3328-CC (Renegade) is a powerful SBC platform powered by the Rockchip RK3328 SoC and equipped with high bandwidth DDR4. It features high performance IO like Gigabit Ethernet and USB 3.0 operating near native speeds. It is perfect for media center and IO intensive applications.

The Firefly Team, who designed this board with us, has accumulated and digested various guides into coherent documentation and put them here:

Since the board has only been out for two months, there is only sparse documentation available on the web so this is a great central resource for getting started with the Renegade. Did we mention that it is backed by GitHub it can be improved upon?

The documentation covers images for Android, Ubuntu, and LibreELEC by the Firefly team based on Rockchip’s SDK (Linux 4.4 LTS). We will also be rolling out Ubuntu 16.04 Xenial and Ubuntu 18.04 Bionic images for Renegade based on the latest upstream Linux LTS as soon as we are able to digest and test patches that are needed. We have no concrete timeline yet but will provide updates when we are close.