diff --git a/README.md b/README.md
index 24b8416..3759220 100644
--- a/README.md
+++ b/README.md
@@ -10,4 +10,4 @@ Hardware accelerated [Julia set](https://en.wikipedia.org/wiki/Julia_set) explor
 Distributed under the [MIT license](https://github.com/Tosainu/ultra96-fractal/blob/master/LICENSE) except these files.
 
 - [petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/*](https://github.com/Tosainu/ultra96-fractal/tree/master/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal)
-    - [Dual MIT/GNU Public License v2](https://github.com/Tosainu/ultra96-fractal/blob/master/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/COPYING)
+    - [GNU General Public License v2.0](https://github.com/Tosainu/ultra96-fractal/blob/master/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/COPYING)
diff --git a/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/COPYING b/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/COPYING
index be09b60..6d45519 100644
--- a/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/COPYING
+++ b/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/COPYING
@@ -338,27 +338,3 @@ proprietary programs.  If your program is a subroutine library, you may
 consider it more useful to permit linking proprietary applications with the
 library.  If this is what you want to do, use the GNU Library General
 Public License instead of this License.
-
---------------------------------------------------------------------------------
-
-MIT License
-
-Copyright (c) 2019 Tosainu
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.
diff --git a/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/fractal.c b/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/fractal.c
index c9e2d5a..ad42e08 100644
--- a/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/fractal.c
+++ b/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/files/fractal.c
@@ -1,5 +1,10 @@
-// SPDX-License-Identifier: GPL-2.0 OR MIT
-/* Copyright (c) 2019 Tosainu. */
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2019 Tosainu.
+ *
+ * This implementation is based on Xilinx Test Pattern Generator driver.
+ * https://github.com/Xilinx/linux-xlnx/blob/xilinx-v2018.3/drivers/media/platform/xilinx/xilinx-tpg.c
+ */
 
 #include <linux/bitops.h>
 #include <linux/clk.h>
@@ -307,4 +312,4 @@ module_platform_driver(fractal_driver);
 
 MODULE_AUTHOR("Tosainu <tosainu.maple@gmail.com>");
 MODULE_DESCRIPTION("Fractal generator driver");
-MODULE_LICENSE("Dual MIT/GPL");
+MODULE_LICENSE("GPL v2");
diff --git a/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/kernel-module-fractal.bb b/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/kernel-module-fractal.bb
index c5b3cc0..c0c6b3a 100644
--- a/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/kernel-module-fractal.bb
+++ b/petalinux_project/project-spec/meta-user/recipes-modules/kernel-module-fractal/kernel-module-fractal.bb
@@ -1,7 +1,7 @@
 SUMMARY = "Recipe for  build an external kernel-module-fractal Linux kernel module"
 SECTION = "PETALINUX/modules"
-LICENSE = "GPLv2 | MIT"
-LIC_FILES_CHKSUM = "file://COPYING;md5=b4f53902635ed0c03c89257898d34521"
+LICENSE = "GPLv2"
+LIC_FILES_CHKSUM = "file://COPYING;md5=12f884d2ae1ff87c09e5b7ccc2c4ca7e"
 
 inherit module