Sound requires several elements (kernel , scripts, settings, etc.). All these elements are present only in the latest images. If you update only the kernel (without adding other necessary elements) in older versions, the sound will not work.
Yes, I know, this only shows up on some AML chips.
Compiling the kernel with a direct reference to files is a bad practice, it may be suitable for personal use, but it is not suitable for mass use. May need to correct the IDs to correctly identify the desired firmware (or rename firmware them).