EDID firmware for 800x480 lcd loading failed

Hi!

SBC : OrangePi Zero 2 + (H3)

Distro: ARMBIAN 5.76 stable Debian GNU/Linux 9 (stretch) 4.19.21-sunxi

First when I ran : sudo armbianmonitor -u

reply is :  System diagnosis information will now be uploaded to Please post the URL in the forum where you've been asked for.

Now my problem:

I am using Armbian for quite a time and it is wonderful. I am trying to connect a waveshare clone 7 inch lcd  with a 800x480 resolution, as the EDID information which lcd provides is broken, I have to force EDID firmware for 800x480 which is already available in the /lib/firmware/edid directory , previously it was working in mainline kernel , but now it refuse to load the same as I upgraded to stretch 4.19.21.

/boot/armbianEnv.txt:

verbosity=1
logo=disabled
console=both
edid=0
disp_mode=800x480
extraargs=drm.edid_firmware=edid/800x480.bin
overlay_prefix=sun8i-h3
overlays=analog-codec usbhost2 usbhost3
rootdev=UUID=b0cad4ec-9479-4799-9d45-6ca4d9b3da22
rootfstype=ext4
usbstoragequirks=0x2537:0x1066:u,0x2537:0x1068:

dmesg :

1.895908] platform HDMI-A-1: Direct firmware load for edid/800x480.bin failed with error -2
[    1.895916] platform HDMI-A-1: Falling back to syfs fallback for: edid/800x480.bin
[   62.458285] [drm:drm_load_edid_firmware] *ERROR* Requesting EDID firmware "edid/800x480.bin" failed (err=-11)
[   63.867927] platform HDMI-A-1: Direct firmware load for edid/800x480.bin failed with error -2
[   63.867943] platform HDMI-A-1: Falling back to syfs fallback for: edid/800x480.bin
[   64.141303] [drm:drm_load_edid_firmware] *ERROR* Requesting EDID firmware "edid/800x480.bin" failed (err=-11)

if I change the /boot/armbianEnv.txt file as under

extraargs=drm.edid_firmware=edid/800x480.bin

to

extraargs=drm.edid_firmware=edid/800x600.bin

dmesg:

[    1.893325] [drm] Got built-in EDID base block and 0 extensions from "edid/800x600.bin" for connector "HDMI-A-1"
[    3.194872] [drm] Got built-in EDID base block and 0 extensions from "edid/800x600.bin" for connector "HDMI-A-1"

it works for 800x600 resolution , so maybe kernel is loading 800x600.bin but not 800x480.bin.

Kindly suggest me a solution.

Best regards