The kernel must match:
The Android kernel is the heart of your device. When you download and install a custom one, you’re not just tweaking software—you’re taking control of the hardware itself. Do it carefully, do it informed, and enjoy the true freedom of Android. download kernel for android
You will get a file named zImage or Image.gz . That is the kernel. ROMs often use a device_* tree that points to a prebuilt kernel binary to save compilation time. The kernel must match: The Android kernel is
If you are just building a custom ROM (AOSP) and don't need to modify the kernel itself, do it informed