One of the things I’ve learned with building a custom kernel is to Read the friendly Wiki page or (RTFW) as other so like to display.
If you’re building the kernel on a 64 bit system, make sure your make commands are:
make ARCH=i386 <command>
So when you’re doing the menuconfig do:
make ARCH=i386 menuconfig
Then make your changes and save the new config.
Then when you create the bzImage file do:
make ARCH=i386 bzImage.
I would almost recommend making this an actual part of the WIKI rather than just a note, as it wouldn’t hurt anything to do this from any platform whether i386 or 64 bit.
Thank you,