title: Buildroot - how to customise an existing kernel defconfig
body: <p>I would like to know how to build a custom kernel defconfig (based on the standard <code>bcmrpi</code> defconfig as a starting point), using Buildroot's ncurses interfaces.</p>
  
  <p>I currently have <code>Kernel configuration -&gt; Using an in-tree defconfig file</code> selected in the Buildroot menuconfig, with <code>bcmrpi</code> as the <code>Defconfig name</code>.</p>
  
  <p>I have tried making some changes to the kernel with make <code>linux-menuconfig</code> but when I try to compile it with <code>make clean</code> the changes are not built, and when I check <code>linux-menuconfig</code> afterwards they have been reset back to the <code>bcmrpi</code> settings.</p>
  
  <p>I would like to be change some settings from these defaults, and then save the resulting settings into a new defconfig, similar to how Buildroot does <code>make savedefconfig</code>, but for the kernel. What command do I use?</p>