diff --git a/post-build.sh b/post-build.sh
index 4b1f177..9c1ae6d 100755
--- a/post-build.sh
+++ b/post-build.sh
@@ -5,10 +5,6 @@ set -e
 
 . "${CONFIGDIR:=${PWD}}"/config
 
-cp -uv \
-    /usr/${target}/boot/*.bin \
-    /usr/${target}/boot/*.dat \
-    /usr/${target}/boot/*.elf \
-    /usr/${target}/usr/share/u-boot/u-boot.bin \
-    config.txt \
-    "$1"/efi-part/
+if [ -f "${CONFIGDIR}"/post-build.sh ]; then
+    . "${CONFIGDIR}"/post-build.sh
+fi
diff --git a/config.txt b/yellow/config.txt
similarity index 100%
rename from config.txt
rename to yellow/config.txt
diff --git a/yellow/post-build.sh b/yellow/post-build.sh
new file mode 100644
index 0000000..10f74fa
--- /dev/null
+++ b/yellow/post-build.sh
@@ -0,0 +1,9 @@
+# vim: set ft=sh sw=4 ts=4 sts=4 et :
+
+cp -uv \
+    /usr/${target}/boot/*.bin \
+    /usr/${target}/boot/*.dat \
+    /usr/${target}/boot/*.elf \
+    /usr/${target}/usr/share/u-boot/u-boot.bin \
+    "${CONFIGDIR}"/config.txt \
+    "$1"/efi-part/