V23.05.2 with different kernel versions?

dave14305,

That rule is in my include/kernel-defaults.mk:

    grep '=[ym]' $(LINUX_DIR)/.config.set | LC_ALL=C sort | $(MKHASH) md5 > $(LINUX_DIR)/.vermagic

The vermagic is a hash of the chosen kernel options. The best advice is to build using the config.seed file from your target.

Where do I find the config.seed of my target (ZyXEL P-2812HNU-F1)?
There is no config.seed at: https://downloads.openwrt.org/releases/23.05.2/targets/lantiq/xrx200/

The Download Selector has a version of my device, why can I not make it -a good working version- myself?

DGDodo