The value is: KERNEL_REVISION_CHECKING ?= "t" Should be: KERNEL_REVISION_CHECKING ?= "y" The "meta/classes/kernel-yocto.bbclass" file tests only if length of the KERNEL_REVISION_CHECKING is non-zero. In this case a value doesn't matter. I think should test for either y or n.
The test for non-zero is intentional. There are multiple different layers and use cases that are using different values. I don't control them all, so unifying on y/t isn't important so simply testing for the existence of this is the easiest way to do this. There are migration plans for this in the future, so leaving this as is for now is the best course of action.
changing state. It didn't stick last time.