It's good you have the panel up and running once Android has completed booting.
Regarding LK, unfortunately as you point out there need to be some modifications made to LK to add support during the boot stage, which is complicated because LK is signed and we cannot release the tools required to sign the image.
If you attempt to load an unsigned LK onto the Open-Q™ 820 dev kit you will 'brick' the device, so please do not do that. The only remedy would be to return the unit to us for reprogramming.
To make changes to LK, we can certainly help by making changes on your behalf and creating a custom signed LK for your specific product. Please contact email@example.com if you wish to pursue this option.