800x480 HDMI lcd not working with my BigTreeTech CB2.

Sat, 01 Aug 2026 11:01:26 +0000

Hi, ive been trying to resolve the screen issue issue on my cb2 for a few days now, i cannot get it to work.

I'm running Armbian_26.2.1_Bigtreetech-cb2_trixie_current_6.18.8_minimal, everything works. HDMI outputs to a 4K display just fine except for my small 5" display, which just stays black. The os has not been tempered with, i've flashed a fresh copy and used armbian-upgrade it, thats all.

I've diagnosed the problem enough to see that its an EDID issue or the rk3566 just not likely my weird screen resolution. BTT os who also use armbian as a base somehow fixed this official issue.

The display is being detected by the OS.

My Armbian OS:
root@bigtreetech-cb2:~# cat /sys/class/drm/card0-HDMI-A-1/status
connected

Display modes in my arbian is empty but BTT armbian fork has the correct modes.

My Armbian OS:
root@bigtreetech-cb2:~# cat /sys/class/drm/card0-HDMI-A-1/modes
root@bigtreetech-cb2:~# 

BTT OS:
root@bigtreetech-cb2:~# cat /sys/class/drm/card0-HDMI-A-1/modes 
800x480 
640x480
640x480

My Armbian OS:
root@bigtreetech-cb2:~# dmesg | grep -Ei "hdmi|drm|edid|display"
[    0.093021] /vop@fe040000: Fixed dependency cycle(s) with /hdmi@fe0a0000
[    0.093163] /hdmi@fe0a0000: Fixed dependency cycle(s) with /vop@fe040000
[    0.131119] /hdmi@fe0a0000: Fixed dependency cycle(s) with /hdmi-con
[    0.131254] /hdmi-con: Fixed dependency cycle(s) with /hdmi@fe0a0000
[    4.047126] rockchip-drm display-subsystem: bound fe040000.vop (ops vop2_component_ops [rockchipdrm])
[    4.061272] dwhdmi-rockchip fe0a0000.hdmi: Detected HDMI TX controller v2.11a with HDCP (DWC HDMI 2.0 TX PHY)
[    4.062694] dwhdmi-rockchip fe0a0000.hdmi: registered DesignWare HDMI I2C bus driver
[    4.067059] rockchip-drm display-subsystem: bound fe0a0000.hdmi (ops dw_hdmi_rockchip_ops [rockchipdrm])
[    4.068415] [drm] Initialized rockchip 1.0.0 for display-subsystem on minor 0
[    4.249136] rockchip-drm display-subsystem: [drm] Cannot find any crtc or sizes
[    4.368820] rockchip-drm display-subsystem: [drm] Cannot find any crtc or sizes
[    8.271095] systemd[1]: Starting modprobe@drm.service - Load Kernel Module drm...
[    8.390055] systemd[1]: modprobe@drm.service: Deactivated successfully.
[    8.391059] systemd[1]: Finished modprobe@drm.service - Load Kernel Module drm.
[   10.653965] [drm] Initialized panfrost 1.4.0 for fde60000.gpu on minor 1
[   11.256108] hdmi-audio-codec hdmi-audio-codec.12.auto: HDMI: Unknown ELD version 0

My Armbian OS:
root@bigtreetech-cb2:~# edid-decode /sys/class/drm/card0-HDMI-A-1/edid
edid-decode (hex):

00 ff ff ff ff ff ff 00 04 72 18 00 db 8d 10 20
01 16 01 03 80 0b 06 78 08 67 60 a2 5a 49 9e 23
13 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 91 0b 20 8c 30 e0 2d 10 10 3c
69 00 20 e0 31 00 00 18 00 00 00 fd 00 37 41 1e
28 03 00 0a 20 20 20 20 20 20 00 00 00 10 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
00 41 63 65 72 20 47 35 30 0a 20 20 20 20 01 27

02 03 1a 41 47 01 01 01 01 01 01 01 23 09 07 07
83 01 00 00 65 03 0c 00 10 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10

----------------

Block 0, Base EDID:
  EDID Structure Version & Revision: 1.3
  Vendor & Product Identification:
    Manufacturer: ACR
    Model: 24
    Serial Number: 537955803
    Made in: week 1 of 2012
  Basic Display Parameters & Features:
    Digital display
    Maximum image size: 11 cm x 6 cm
    Gamma: 2.20
    RGB color display
  Color Characteristics:
    Red  : 0.6337, 0.3535
    Green: 0.2861, 0.6201
    Blue : 0.1376, 0.0761
    White: 0.3125, 0.3281
  Established Timings I & II: none
  Standard Timings: none
  Detailed Timing Descriptors:
    DTD 1:   800x480    60.000000 Hz   5:3     31.500 kHz     29.610000 MHz (800 mm x 480 mm)
                 Hfront   16 Hsync  60 Hback   64 Hpol N
                 Vfront    6 Vsync   9 Vback   30 Vpol N
    Display Range Limits:
      Monitor ranges (GTF): 55-65 Hz V, 30-40 kHz H, max dotclock 30 MHz
    Dummy Descriptor:
    Display Product Name: 'Acer G50'
  Extension blocks: 1
Checksum: 0x27

----------------

Block 1, CTA-861 Extension Block:
  Revision: 3
  Basic audio support
  Native detailed modes: 1
  Video Data Block:
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
    VIC   1:   640x480    59.940476 Hz   4:3     31.469 kHz     25.175000 MHz
  Audio Data Block:
    Linear PCM:
      Max channels: 2
      Supported sample rates (kHz): 48 44.1 32
      Supported sample sizes (bits): 24 20 16
  Speaker Allocation Data Block:
    FL/FR - Front Left/Right
  Vendor-Specific Data Block (HDMI), OUI 00-0C-03:
    Source physical address: 1.0.0.0
Checksum: 0x10

BTT OS:
root@bigtreetech-cb2:~# edid-decode /sys/class/drm/card0-HDMI-A-1/edid
edid-decode (hex):

00 ff ff ff ff ff ff 00 04 72 18 00 db 8d 10 20
01 16 01 03 80 0b 06 78 08 67 60 a2 5a 49 9e 23
13 50 54 00 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 91 0b 20 8c 30 e0 2d 10 10 3c
69 00 20 e0 31 00 00 18 00 00 00 fd 00 37 41 1e
28 03 00 0a 20 20 20 20 20 20 00 00 00 10 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc
00 41 63 65 72 20 47 35 30 0a 20 20 20 20 01 27

02 03 1a 41 47 01 01 01 01 01 01 01 23 09 07 07
83 01 00 00 65 03 0c 00 10 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 10

----------------

Block 0, Base EDID:
  EDID Structure Version & Revision: 1.3
  Vendor & Product Identification:
    Manufacturer: ACR
    Model: 24
    Serial Number: 537955803
    Made in: week 1 of 2012
  Basic Display Parameters & Features:
    Digital display
    Maximum image size: 11 cm x 6 cm
    Gamma: 2.20
    RGB color display
  Color Characteristics:
    Red  : 0.6337, 0.3535
    Green: 0.2861, 0.6201
    Blue : 0.1376, 0.0761
    White: 0.3125, 0.3281
  Established Timings I & II: none
  Standard Timings: none
  Detailed Timing Descriptors:
    DTD 1:   800x480    60.000 Hz   5:3    31.500 kHz  29.610 MHz (800 mm x 480 mm)
                 Hfront   16 Hsync  60 Hback  64 Hpol N
                 Vfront    6 Vsync   9 Vback  30 Vpol N
  Display Range Limits:
    Monitor ranges (GTF): 55-65 Hz V, 30-40 kHz H, max dotclock 30 MHz
    Dummy Descriptor:
    Display Product Name: 'Acer G50'
  Extension blocks: 1
Checksum: 0x27

----------------

Block 1, CTA-861 Extension Block:
  Revision: 3
  Basic audio support
  Native detailed modes: 1
  Video Data Block:
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
    VIC   1:   640x480    59.940 Hz   4:3    31.469 kHz  25.175 MHz
  Audio Data Block:
    Linear PCM:
      Max channels: 2
      Supported sample rates (kHz): 48 44.1 32
      Supported sample sizes (bits): 24 20 16
  Speaker Allocation Data Block:
    FL/FR - Front Left/Right
  Vendor-Specific Data Block (HDMI), OUI 00-0C-03:
    Source physical address: 1.0.0.0
Checksum: 0x10

I don't even know if this info is relavent, im new to armbian...so if u need anything else to diagnose this issue, let me know.

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