Troubleshooting • Re: degraded screen at boot on Pi4

Correct. The bootloader will output VGA which is supposed to be supported on all HDMI screens

You can add DISABLE_HDMI=1 in the EEPROM config to stop the bootloader from using the screen.

i@raspberrypi:/sys/class/drm $ cd card1-HDMI-A-1/
pi@raspberrypi:/sys/class/drm/card1-HDMI-A-1 $ edid-decode edid
edid-decode (hex):

00 ff ff ff ff ff ff 00 12 e9 02 2c 41 6f c3 00
01 1d 01 04 81 59 32 78 0a 0d c9 a0 57 47 98 27
12 48 4c 20 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 bc 1b 00 a0 50 20 17 30 30 20
36 00 20 c2 31 00 00 1a bc 1b 00 a0 50 20 17 30
30 20 36 00 20 c2 31 00 00 1a 00 00 00 fc 00 48
44 4d 49 20 50 61 6e 65 6c 20 5a 0a 00 00 00 fd
00 3a 3e 0e 46 08 00 0a 20 20 20 20 20 20 01 00

02 03 16 c0 41 01 23 09 07 07 83 01 00 00 67 03
0c 00 10 00 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 00 00 00 8f

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

Block 0, Base EDID:
EDID Structure Version & Revision: 1.4
Vendor & Product Identification:
Manufacturer: DWI
Model: 11266
Serial Number: 12808001
Made in: week 1 of 2019
Basic Display Parameters & Features:
Digital display
Color depth is undefined
DVI interface
Maximum image size: 89 cm x 50 cm
Gamma: 2.20
Supported color formats: RGB 4:4:4, YCrCb 4:4:4
First detailed timing includes the native pixel format and preferred refresh rate
Color Characteristics:
Red : 0.6250, 0.3398
Green: 0.2802, 0.5947
Blue : 0.1552, 0.0703
White: 0.2832, 0.2978
Established Timings I & II:
DMT 0x04: 640x480 59.940 Hz 4:3 31.469 kHz 25.175 MHz
Standard Timings: none
Detailed Timing Descriptors:
DTD 1: 1280x800 59.910 Hz 8:5 49.306 kHz 71.000 MHz (800 mm x 450 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 6 Vback 14 Vpol N
DTD 2: 1280x800 59.910 Hz 8:5 49.306 kHz 71.000 MHz (800 mm x 450 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 6 Vback 14 Vpol N
Display Product Name: 'HDMI Panel Z'
Display Range Limits:
Monitor ranges (GTF): 58-62 Hz V, 14-70 kHz H, max dotclock 80 MHz
Extension blocks: 1
Checksum: 0x00

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

Block 1, CTA-861 Extension Block:
Revision: 3
Underscans IT Video Formats by default
Basic audio support
Native detailed modes: 0
Video Data Block:
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
Maximum TMDS clock: 80 MHz
Checksum: 0x8f
pi@raspberrypi:/sys/class/drm/card1-HDMI-A-1 $

Statistics: Posted by yaumme — Sat Mar 22, 2025 1:13 pm