Troubleshooting Boot Issues on Libre Computer ROC-RK3328-CC Renegade

Please first reference Troubleshooting General Boot Issues .

  1. After attaching power, the Green and Red LEDs should light up. This indicates that the board is powered. Nothing will show up on HDMI or CVBS yet.
  2. At no point after attaching power should the Red LED blink or turn off. If this happens, it means that your power supply is inadequate. Please make sure that you are using a 5V power supply capable of supplying at least 1.5A (1500mA). Not having enough power could cause spontaneous reboots or software errors.
  3. The board will try to read the bootloader from the eMMC and then the MicroSD card from sector 64 (32KB). If the correct signed bootloader is detected, the board will begin loading it.
  4. After 30 seconds, Linux should be loaded and the Green LED should begin to heartbeat. You should see video on your HDMI display. Certain types of displays with odd resolutions are not supported at this stage and it might not display anything during this step and the next steps. If the Green LED turns green and nothing shows on your screen, please post your screen brand, model, and EDID here.
  5. The bootloader will attempt to EFI boot from a list of block devices:
  • eMMC
  • MicroSD
  • USB Flash Drive
    It looks for an FAT/EFI partition with /boot/bootaa64.efi, loads the file into memory, and executes the it. On our images, bootaa64.efi is GRUB.
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I can confirm by testing my 4 libre boards that … if you install the ubuntu image … this is correct and that the red LED will be constant if powered correctly, and the green LED will double flash a heartbeat every second.

However if you install raspbian or the armbian images. the green led will not be illuminated (it is on boot but only for a few seconds then it goes off) and the red led will instead flash the same double heartbeat pattern every second.

This documentation had me very confused so I am just posting this to try and clarify that some images act differently than others with respect to the LED’s. I apologise in advance if I am mistaken but this is what my testing over the last 3 days has bore out.

Also there is very little info on the small recovery button available, so all i can learn about that is that it is a recovery button and not a reset/power button

great little boards though! thanks again

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Hi Nate,

Have you tried using the libretech-flash-tool to re-image the bootloader on your Renegades? In a thread I started in November of last year regarding a different topic ( [Vdd_arm: ramp_delay not set kernel messages on Renegade]) it was recommended that I do so on my Renegade pair and it not only fixed my ramp_delay issue but it also set the LEDs to work in the way described in the documentation. Both of mine have been running the Libre Raspbian 11 image since December and the LEDs are RED on when running correctly and green pulsing heartbeat. YMMV of course!


Thanks man!, I didn’t even know about that flash tool!. Okay so for clarification, I flashed my images using the raspberry pi imager in all cases where it didn’t work properly and the the lights flashed incorrectly. once i switched to balena etcher then things worked. so I think you are correct there!

Do you think using this flash tool will also fix my issues with 2 of my 4 not automatically coming back on after issuing reboot commands? seems unlikely as they all have the same sd cards, same peripherals same power sources & cables etc. I will try it and find out - thanks for pointing that out!

You should probably head to the libretech-flash-tool git site at GitHub - libre-computer-project/libretech-flash-tool and read how it works. This tool doesn’t work like the Raspberry Pi imager (which is what I also used for my installations) as it only updates the bootloader on an already imaged SD card.

The process that I used, which worked, was using the Raspberry Pi imager to install Raspbian on my pair of Renegades, shutdown the pair after I set them up (while the LEDs were still acting wrong), placed the SD cards into the card reader of one of my Ubuntu machines where I downloaded the tool to and ran this utility on both SD cards. Then when I put the cards back into the Renegades the LEDs worked correctly and my original problem from November were both fixed.

Regarding your rebooting issue, I can’t really speak to that. I have only encountered issues with my Raspberry Pi’s where issuing “shutdown -r now” resulted in them powering down instead. That was back in buster/Raspbian 10 and it was resolved in bullseye/Raspbian 11, but again that was just on some of my Pi’s, not my Renegades.

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libretech-flash-tool is not for the purpose of fixing Armbian LEDs. It is to update the bootloader on existing images to the latest. There are some rare MicroSD card compatibility issues we are still investigating on ROC-RK3328-CC.

Do you know if it’s possible to use the libretech-flash-tool on wsl for windows? Or do I need an Ubuntu environment outside of the libre board itself?

Sorry, I actually do not know if that’s possible or not as I don’t use WSL. Maybe someone else on here has. :slight_smile:

Not sure if WSL has access to raw devices and if it shows them under the normal /dev/{mmc,sd} naming. If WSL does not, then libretech-flash-tool will not work.

I’ve been having issues using the libretech-flash-tool for PXE booting my ROC-RK3328-CC. When I use the tool as the instructions state nothing happens on my board after plugging in the board with the MicroSD card in. Nothing on the screen, solid green and red light


You can change the green and red leds by echoing a value to their triggers.
You can see all the valid values when you run the command:
# cat /sys/class/leds/librecomputer\:green/trigger
You can change the led by the following command:
# echo none > /sys/class/leds/librecomputer\:green/trigger
and replace ‘none’ with any valid value.

No doubt that Armbian is doing this in the boot process.

ROC-RK3328-CC’s bootloader does not support HDMI output yet. But this will be supported as soon as upstream fixes some IOMMU bugs. You have to connect UART. By default, our bootloaders disable networking to both expedite boot time and reduce attack vector so PXE will not be supported out of the box. You have to compile your own bootloader with our libretech-builder-simple.

Hi. I encounter strange behavior using latest linux images (both ubuntu and raspbian). They do not boot at all if HDMI is connected. Even ubuntu base which is without GUI. After power on only red led is constantly on and nothing else happens even after few minutes (network led also not blinking, system not accessible via ssh). If I plug off HDMI cable then after few seconds green led starts blinking and system loads and is fully-functional. If I connect HDMI after that it works. It happens only on images with EFI and GRUB. Images based on extlinux (i.e. LibreElec or old ubuntu from firefly website) works perfectly and boot with HDMI connected, so I assume it is some kind of software problem.

What monitor make and model do you have? We will try to replicate.


parse-edid output

parse-edid < /tmp/edid
Checksum Correct

Section “Monitor”
Identifier “DELL U2723QE”
ModelName “DELL U2723QE”
VendorName “DEL”
# Monitor Manufactured week 28 of 2022
# EDID version 1.3
# Digital Display
DisplaySize 600 340
Gamma 2.20
Option “DPMS” “true”
Horizsync 15-140
VertRefresh 23-86
# Maximum pixel clock is 600MHz
#Not giving standard mode: 1920x1200, 60Hz
#Not giving standard mode: 1920x1080, 60Hz
#Not giving standard mode: 1680x1050, 60Hz
#Not giving standard mode: 1600x1200, 60Hz
#Not giving standard mode: 1280x1024, 60Hz
#Not giving standard mode: 1280x800, 60Hz
#Not giving standard mode: 1152x864, 75Hz
#Not giving standard mode: 2048x1152, 60Hz

#Extension block found. Parsing...

#WARNING: I may have missed a mode (CEA mode 95)
#WARNING: I may have missed a mode (CEA mode 94)
#WARNING: I may have missed a mode (CEA mode 93)
Modeline “Mode 15” 241.50 2560 2608 2640 2720 1440 1443 1448 1481 +hsync -vsync
Modeline “Mode 0” 527.85 3840 3872 3888 3910 2160 2168 2178 2250 +hsync +vsync
Modeline “Mode 1”
Modeline “Mode 2”
Modeline “Mode 3” 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
Modeline “Mode 4” 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
Modeline “Mode 5” 74.250 1920 2558 2602 2750 1080 1084 1089 1125 +hsync +vsync
Modeline “Mode 6” 74.250 1920 2008 2052 2200 1080 1082 1087 1125 +hsync +vsync interlace
Modeline “Mode 7” 74.250 1920 2448 2492 2640 1080 1082 1089 1125 +hsync +vsync interlace
Modeline “Mode 8” 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync
Modeline “Mode 9” 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
Modeline “Mode 10” 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
Modeline “Mode 11” 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
Modeline “Mode 12” 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
Modeline “Mode 13” 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
Modeline “Mode 14” 25.200 640 656 752 800 480 490 492 525 -hsync -vsync
Modeline “Mode 16” 174.25 2048 2096 2128 2208 1280 1283 1289 1311 +hsync -vsync
Modeline “Mode 17” 58.23 2048 2096 2128 2208 1080 1083 1093 1099 +hsync -vsync
Option “PreferredMode” “Mode 15”

But result is same when I connect to samsung tv

Tried another monitor - Lenovo ThinkVision P27h-20, on first moments it show message “Input signal out of range. Please change to 2560x1440@60Hz”, but then booted successfully. By the way it has lower maximum resolution than previous two devices which are 4K.

ROC-RK3328-CC u-boot has new video code that is not very robust yet. We’ll have engineering consultants take a look. Also if you have an UART cable with the logs for these monitors, it would help expedite.

Thank you. Unfortunately currently I have no UART cable, but I ordered one, as soon as it will arrive I’ll try to get logs, if they will be still relevant.

Hi, I’m having a similar issue with HDMI, here’s what I see on the UART during the initial boot process (I can only see the GRUB menu on the UART, never on HDMI):

MIC: RK8050 (on=0x40, off=0x00)
DDR4, 800MHz
BW=32 Col=10 Bk=4 BG=2 CS0 Row=16 CS1 Row=16 CS=2 Die BW=16 Size=4096MB
Trying to boot from BOOTROM
Returning to boot ROM…
Trying to boot from MMC2
lz4 image
NOTICE: BL31: v2.9(release):v2.8-1351-g8929dffc0
NOTICE: BL31: Built : 02:49:07, Jul 31 2023
NOTICE: BL31:Rockchip release version: v1.2

U-Boot 2023.07+ (Jul 31 2023 - 02:49:10 -0400) Libre Computer ROC-RK3328-CC

PMIC: RK8050 (on=0x40, off=0x00)
Core: 244 devices, 31 uclasses, devicetree: separate
MMC: mmc@ff500000: 1, mmc@ff520000: 0
Loading Environment from FAT… Unable to read “uboot.env” from mmc0:1…
Error (-2): cannot determine file size
unsupported rate 18446744073709551615
TMDS clock is zero!
inno_hdmi_phy phy@ff430000: PHY: Failed to power on phy@ff430000: -22.
failed to on hdmi phy (ret=-22)
unsupported rate 18446744073709551615
TMDS clock is zero!
inno_hdmi_phy phy@ff430000: PHY: Failed to power on phy@ff430000: -22.
failed to on hdmi phy (ret=-22)
unsupported rate 18446744073709551615
TMDS clock is zero!
inno_hdmi_phy phy@ff430000: PHY: Failed to power on phy@ff430000: -22.
failed to on hdmi phy (ret=-22)
U-Boot 2023.07+ (Jul 31 2023 - 02:49:10 -0400) Libre Computer ROC-RK3328-CC

Model: Libre Computer ROC-RK3328-CC
starting USB…
Bus usb@ff5c0000: USB EHCI 1.00
Bus usb@ff5d0000: USB OHCI 1.0
Bus usb@ff600000: generic_phy_get_bulk : no phys property
Register 2000140 NbrPorts 2
Starting the controller
Bus usb@ff580000: USB DWC2
scanning bus usb@ff5c0000 for devices… 1 USB Device(s) found
scanning bus usb@ff5d0000 for devices… 2 USB Device(s) found
scanning bus usb@ff600000 for devices… 1 USB Device(s) found
scanning bus usb@ff580000 for devices… 2 USB Device(s) found
scanning usb for storage devices… 0 Storage Device(s) found
Hit any key to stop autoboot: 0
Scanning for bootflows in all bootdevs
Seq Method State Uclass Part Name Filename

Scanning global bootmeth ‘efi_mgr’:
Scanning bootdev ‘mmc@ff520000.bootdev’:
0 efi ready mmc 1 mmc@ff520000.bootdev.part efi/boot/bootaa64.efi
** Booting bootflow ‘mmc@ff520000.bootdev.part_1’ with efi
unsupported rate 18446744073709551615
TMDS clock is zero!
inno_hdmi_phy phy@ff430000: PHY: Failed to power on phy@ff430000: -22.
failed to on hdmi phy (ret=-22)
Booting /efi\boot\bootaa64.efi

                         GNU GRUB  version 2.06

(I’m using a Belkin HDMI to VGA adapter :wink: )

Here’s my Raspbian xrandr output:
Screen 0: minimum 320 x 200, current 1280 x 720, maximum 4096 x 4096
HDMI-1 connected primary 1280x720+0+0 (normal left inverted right x axis y axis) 410mm x 230mm
1280x720 60.00* 50.00
1024x768 60.00
800x600 60.32
720x480 59.94

These boards only support HDMI based displays. There’s no VGA signal unless you use an active adapter and even then the timings will not work since those DVI/VGA displays do not use HDMI standard timings.