diff --git a/.gitignore b/.gitignore
index 9aad7a2..1528bde 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,3 @@
 /output
-/customizations/users.table
-/customizations/overlay/
+/external_tree/customizations/users.table
+/external_tree/customizations/overlay/
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..e1d58ff
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "buildroot"]
+	path = buildroot
+	url = https://github.com/buildroot/buildroot.git
diff --git a/buildroot b/buildroot
new file mode 160000
index 0000000..69f79f2
--- /dev/null
+++ b/buildroot
@@ -0,0 +1 @@
+Subproject commit 69f79f2a2ee1417e19c1ead2c9226e11753c06cb
diff --git a/buildroot_make.sh b/buildroot_make.sh
index 9c2567d..921a6af 100755
--- a/buildroot_make.sh
+++ b/buildroot_make.sh
@@ -1,8 +1,3 @@
 #!/bin/bash
 
-if [ -z ${BUILDROOT_PATH} ]; then
-  echo "BUILDROOT_PATH environment variable is not set."
-  exit
-fi
-
-make O=${PWD}/output BR2_EXTERNAL=${PWD} -C ${BUILDROOT_PATH} "$@"
+make O=${PWD}/output BR2_EXTERNAL=${PWD}/external_tree -C buildroot "$@"
diff --git a/Config.in b/external_tree/Config.in
similarity index 100%
rename from Config.in
rename to external_tree/Config.in
diff --git a/LICENSE b/external_tree/LICENSE
similarity index 100%
rename from LICENSE
rename to external_tree/LICENSE
diff --git a/README.md b/external_tree/README.md
similarity index 100%
rename from README.md
rename to external_tree/README.md
diff --git a/board/.gitkeep b/external_tree/board/.gitkeep
similarity index 100%
rename from board/.gitkeep
rename to external_tree/board/.gitkeep
diff --git a/board/iminc/orangepi-pc-system-agent/boot.cmd b/external_tree/board/iminc/orangepi-pc-system-agent/boot.cmd
similarity index 100%
rename from board/iminc/orangepi-pc-system-agent/boot.cmd
rename to external_tree/board/iminc/orangepi-pc-system-agent/boot.cmd
diff --git a/board/iminc/orangepi-pc-system-agent/genimage.cfg b/external_tree/board/iminc/orangepi-pc-system-agent/genimage.cfg
similarity index 100%
rename from board/iminc/orangepi-pc-system-agent/genimage.cfg
rename to external_tree/board/iminc/orangepi-pc-system-agent/genimage.cfg
diff --git a/board/iminc/orangepi-pc-system-agent/linux.fragment b/external_tree/board/iminc/orangepi-pc-system-agent/linux.fragment
similarity index 100%
rename from board/iminc/orangepi-pc-system-agent/linux.fragment
rename to external_tree/board/iminc/orangepi-pc-system-agent/linux.fragment
diff --git a/board/iminc/orangepi-pc-system-agent/readme.txt b/external_tree/board/iminc/orangepi-pc-system-agent/readme.txt
similarity index 100%
rename from board/iminc/orangepi-pc-system-agent/readme.txt
rename to external_tree/board/iminc/orangepi-pc-system-agent/readme.txt
diff --git a/board/iminc/orangepi-pc-system-agent/uboot.fragment b/external_tree/board/iminc/orangepi-pc-system-agent/uboot.fragment
similarity index 100%
rename from board/iminc/orangepi-pc-system-agent/uboot.fragment
rename to external_tree/board/iminc/orangepi-pc-system-agent/uboot.fragment
diff --git a/board/iminc/pine64-a64-plus-system-agent/boot.cmd b/external_tree/board/iminc/pine64-a64-plus-system-agent/boot.cmd
similarity index 100%
rename from board/iminc/pine64-a64-plus-system-agent/boot.cmd
rename to external_tree/board/iminc/pine64-a64-plus-system-agent/boot.cmd
diff --git a/board/iminc/pine64-a64-plus-system-agent/genimage.cfg b/external_tree/board/iminc/pine64-a64-plus-system-agent/genimage.cfg
similarity index 100%
rename from board/iminc/pine64-a64-plus-system-agent/genimage.cfg
rename to external_tree/board/iminc/pine64-a64-plus-system-agent/genimage.cfg
diff --git a/board/iminc/pine64-a64-plus-system-agent/linux.fragment b/external_tree/board/iminc/pine64-a64-plus-system-agent/linux.fragment
similarity index 100%
rename from board/iminc/pine64-a64-plus-system-agent/linux.fragment
rename to external_tree/board/iminc/pine64-a64-plus-system-agent/linux.fragment
diff --git a/board/iminc/pine64-a64-plus-system-agent/pine64_a64_plus_defconfig b/external_tree/board/iminc/pine64-a64-plus-system-agent/pine64_a64_plus_defconfig
similarity index 100%
rename from board/iminc/pine64-a64-plus-system-agent/pine64_a64_plus_defconfig
rename to external_tree/board/iminc/pine64-a64-plus-system-agent/pine64_a64_plus_defconfig
diff --git a/board/iminc/pine64-a64-plus-system-agent/uboot.fragment b/external_tree/board/iminc/pine64-a64-plus-system-agent/uboot.fragment
similarity index 100%
rename from board/iminc/pine64-a64-plus-system-agent/uboot.fragment
rename to external_tree/board/iminc/pine64-a64-plus-system-agent/uboot.fragment
diff --git a/configs/.gitkeep b/external_tree/configs/.gitkeep
similarity index 100%
rename from configs/.gitkeep
rename to external_tree/configs/.gitkeep
diff --git a/configs/orangepi_pc_system_agent_defconfig b/external_tree/configs/orangepi_pc_system_agent_defconfig
similarity index 100%
rename from configs/orangepi_pc_system_agent_defconfig
rename to external_tree/configs/orangepi_pc_system_agent_defconfig
diff --git a/configs/pine64_a64_plus_defconfig b/external_tree/configs/pine64_a64_plus_defconfig
similarity index 100%
rename from configs/pine64_a64_plus_defconfig
rename to external_tree/configs/pine64_a64_plus_defconfig
diff --git a/customizations/users.table.example b/external_tree/customizations/users.table.example
similarity index 100%
rename from customizations/users.table.example
rename to external_tree/customizations/users.table.example
diff --git a/external.desc b/external_tree/external.desc
similarity index 100%
rename from external.desc
rename to external_tree/external.desc
diff --git a/external.mk b/external_tree/external.mk
similarity index 100%
rename from external.mk
rename to external_tree/external.mk
diff --git a/package/.gitkeep b/external_tree/package/.gitkeep
similarity index 100%
rename from package/.gitkeep
rename to external_tree/package/.gitkeep