unfortunately, my serial console is broken but it seems I am not able to conenct to the LS1021A-IOT board via ssh or telnet (telnet was working with "old" OpenWrt image).
I am not able to ping to 196.168.1.1 with an ethernet point-to-point connection.
PROBLEM 2: Second problem is: is there a way for flashing OpenWrt in QSPI flash instead of SD card boot?
Without serial to see why it isn’t booting you are basically out of luck. You could try a 19 series firmware to see if you have any luck there, or change sd cards?
Ok, looking at the commit for the device it says ext4 images only will work, though no clear reason why.
Images were ext4 until v22 when they changed to squash for this device.
Try a v19 and see if it boots, if it does then build an ext4 v22 image and upgrade to that.
As for why these are sd card only, perhaps reach out to the original submitter of the commit and ask why they went that way.
It's been a while since I used my NXP LS1021AIOT, but I recall having to build the image myself for some reason. It could have been that the ext4 image was not available and squash image did not work. I don't have easy access to the device right now or I would check. However I think @jdwl1o1 might be correct that you will need to build an ext4 image.