ref-manual: document image-specific variant of INCOMPATIBLE_LICENSE

This has been around without being properly documented since 2019 (!!!),
and is nowadays the preferred method for enforcing license restrictions,
especially since meta-gplv2 is officially obsolete.

(From yocto-docs rev: efa1c57ecec934998792b7851b4a162be92c8b23)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 9 insertions, 7 deletions

diff --git a/documentation/ref-manual/images.rst b/documentation/ref-manual/images.rst
index d3aeb0829f..0f6d6bdb3f 100644
--- a/documentation/ref-manual/images.rst
+++ b/documentation/ref-manual/images.rst
@@ -14,15 +14,17 @@ image you want.
    Building an image without GNU General Public License Version 3
    (GPLv3), GNU Lesser General Public License Version 3 (LGPLv3), and
    the GNU Affero General Public License Version 3 (AGPL-3.0) components
-   is only supported for minimal and base images. Furthermore, if you
-   are going to build an image using non-GPLv3 and similarly licensed
-   components, you must make the following changes in the ``local.conf``
-   file before using the BitBake command to build the minimal or base
-   image:
+   is only tested for core-image-minimal image. Furthermore, if you would like to
+   build an image and verify that it does not include GPLv3 and similarly licensed
+   components, you must make the following changes in the image recipe
+   file before using the BitBake command to build the image:
 
-   #. Comment out the :term:`EXTRA_IMAGE_FEATURES` line
+       INCOMPATIBLE_LICENSE = "GPL-3.0* LGPL-3.0*"
 
-   #. Set :term:`INCOMPATIBLE_LICENSE` to "GPL-3.0* LGPL-3.0* AGPL-3.0*"
+   Alternatively, you can adjust ``local.conf`` file, repeating and adjusting the line
+   for all images where the license restriction must apply:
+
+       INCOMPATIBLE_LICENSE:pn-your-image-name = "GPL-3.0* LGPL-3.0*"
 
 From within the ``poky`` Git repository, you can use the following
 command to display the list of directories within the :term:`Source Directory`