I downloaded Tinker_Board_2-Debian-Buster-v2.0.4-20211222.zip for a Tinker Board 2 and it has the 4.4.194 kernel, which I believe is in the linux4.4-rk3288-tinker_board branch. Hopefully this is correct and I can figure out the correct configuration so that the headers match. I need to have usblp.ko available to communicate with receipt printers.
Can you, in the future, include usblp.ko as a loadable kernel module? This way I can just use modprobe to configure the system to load the module. If it interferes with CUPS you can always make it not load by defaut, but it needs to at least exist in /lib to avoid having to search for the correct kernel version etc. and build it myself.