AlexanderTN

Try different monitor indeed helps.
So this is my case (just have time to test it this morning) that explain the issue I met):
- in 2020 I tried a full HD Dell monitor and I can see the boot screen and logs from that monitor
- in 2023 I tried again on a 2K LG monitor and it shows nothing on screen
 
So as SteeMan said : SD card quality and  monitor type are the factor we need to check when we encounter this 'HDMI boot issue'
Cheers.

I had this problem too, thank the user B1oHazard I solved it. The problem is the NAND frequency in the .dtb... some x96 mini have a different nand. To fix it, you need to change the .dtb file:
 
You need to unpack your dtb file into dts via device-tree-compile tool. Install it in linux ubuntu using 
sudo apt-get install device-tree-compiler decompile the dtb file:
dtc -I dtb -O dts -o meson-gxl-s905w-p281.dts meson-gxl-s905w-p281.dtb edit this file searching for "mmc@74000" block
max-frequency = <0x5f5e100>;
5f5e100 in hex = 100000000 in dec
edit it to 0x2faf080, 50000000 in dec
compile with
dtc -I dts -O dtb -o meson-gxl-s905w-p281.dtb meson-gxl-s905w-p281.dts  
for  Armbian_20.10_Arm-64_focal_current_5.9.0.img I prepared the file for you (see attachment)
meson-gxl-s905w-p281.dtb