variables: clarify KERNEL_ALT_IMAGETYPE reference

Make it clear that KERNEL_ALT_IMAGETYPE is intended to allow building an
additional image type.

(From yocto-docs rev: d2f51d310028dfa50584f7dc04ea3627d14d3f1e)

Signed-off-by: Paul Eggleton <paul.eggleton@microsoft.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/documentation/ref-manual/variables.rst b/documentation/ref-manual/variables.rst
index 8c6cc46b6c..4508bb1451 100644
--- a/documentation/ref-manual/variables.rst
+++ b/documentation/ref-manual/variables.rst
@@ -3983,8 +3983,9 @@ system and gives an overview of their function and contents.
       when building the kernel and is passed to ``make`` as the target to
       build.
 
-      If you want to build an alternate kernel image type, use the
-      :term:`KERNEL_ALT_IMAGETYPE` variable.
+      If you want to build an alternate kernel image type in addition to that
+      specified by ``KERNEL_IMAGETYPE``, use the :term:`KERNEL_ALT_IMAGETYPE`
+      variable.
 
    :term:`KERNEL_MODULE_AUTOLOAD`
       Lists kernel modules that need to be auto-loaded during boot.