Looking for help porting to an RK3328-based device

[QwertyChouskie]

I'm looking for help porting to an RK3328-based device, the REV Robotics Control Hub.  It ships running a custom version of Android 7.  The compute board's physical layout is based on the 96Boards CE spec, and is visibly extremely similar to the Dragonboard 410c (https://www.96boards.org/product/dragonboard410c/).  It has these specs and ports:

- Rockchip RK3328 SOC
- Rockchip RK805-1 (I believe from my research that this is a power management chip?)

- 1GB DDR3 RAM (2x Samsung K4B4G1646E-BYMA chips)

- 16GB eMMC (Samsung KLMAG1JETD-B041)
  - Oddly, the manufacturer specs list this device as having 8GB eMMC 4.51, but the chip on my board at least is 16GB eMMC 5.1.

  - I seem to have managed to kill the eMMC on my board during testing, so for now, I have to boot off of MicroSD

- RTL8821CU WiFi/BT chip
- 1x USB 3.0 Type A port

- 1x USB 2.0 Type A port

- 1x USB-C port
- HDMI

- MicroSD card reader

- 40 pin low speed expansion connector

  - I believe specifically the UART on this connector is what is used to communicate with the other board in the device

- Internal UART connector for debugging

  - I have successfully connected to it, and can view debug output from the boot process and interact with u-boot.

 

- The manufacturer's u-boot: https://github.com/REVrobotics/u-boot-controlhub-android

- The manufacturer's Android kernel: https://github.com/REVrobotics/kernel-controlhub-android
  - Makefile: https://github.com/REVrobotics/kernel-controlhub-android/blob/main/arch/arm64/boot/dts/Makefile
  - defconfig: https://github.com/REVrobotics/kernel-controlhub-android/blob/main/arch/arm64/configs/rockchip_smp_nougat_defconfig

 

The ROC-RK3328-CC "Renegade" SBC (https://libre.computer/products/roc-rk3328-cc/) is similar enough that some OS images designed for it can run on the Control Hub board
  - OS images are in the Downloads section of the page
  - Armbian has builds available for it: https://www.armbian.com/renegade/
  - Firefly also has older OS images: https://en.t-firefly.com/doc/download/65.html

    - Android 7.1 boot and displays, but has no working USB
    - Android 8.1 and Ubuntu 18.04 confirmed to flash successfully and have HDMI and the USB 3 port working, but no USB 2 or Wi-Fi
      - `sudo ./xrock reset maskrom` needed while board is in loader mode to put it into Mask ROM mode, otherwise OS installation using `upgrade_tool` may fail

    - These images won't successfully boot off of MicroSD, only the internal eMMC.

 

If anyone has any guidance on how to go about this port, I would deeply appreciate it.  Everything I have figured out so far is just via countless hours of trial and error; I'm not even close to being an expert on any of this stuff.

[SteeMan]

Have you tried the generic rk3328 builds found discussed in this thread: 

 

 

I would start there by reading that thread.  Your box likely has a lot in common with what is discussed there.

[QwertyChouskie]

@SteeMan Thanks!  With the "Armbian_community_25.8.0-trunk.411_Rk3318-box_bookworm_current_6.12.40_minimal" image, and enabling "rk3318-box-led-conf3", I was able to get working USB 3.0, USB 2.0, WiFi, and HDMI!  My biggest hold-up now is getting the UART on the GPIO header working (not the debugging UART, that works fine).  I tried enabling the "rk3328-uart1" overlay, but no additional devices showed up in "/dev".  Is it supposed to show up as a serial device, or what is the way to access that UART?

[IBV]

Hi,

 

if it is similar to the tinkerboard, you should enable the overlay using "overlays=uart1", and the /dev/ttyS1 should be the serial port.

What does "dmesg | grep ttyS" say?

 

[QwertyChouskie]

On 8/5/2025 at 7:28 AM, IBV said:

Hi,

 

if it is similar to the tinkerboard, you should enable the overlay using "overlays=uart1", and the /dev/ttyS1 should be the serial port.

What does "dmesg | grep ttyS" say?

Turns out /dev/ttyS1 works perfectly!  I was thrown off by the fact that it exists whether the overlay is enabled or not, but only works with the overlay enabled.  With the overlay enabled, using /dev/ttyS1 worked perfectly.

[IBV]

Good news!