diff --git a/target/imagebuilder/Makefile b/target/imagebuilder/Makefile
index 0580e41c57..8607a2d709 100644
--- a/target/imagebuilder/Makefile
+++ b/target/imagebuilder/Makefile
@@ -46,12 +46,16 @@ ifeq ($(CONFIG_IB_STANDALONE),)
 	$(VERSION_SED_SCRIPT) $(PKG_BUILD_DIR)/repositories.conf
 endif
 
-ifeq ($(CONFIG_BUILDBOT),)
 	$(INSTALL_DIR) $(PKG_BUILD_DIR)/packages
+	# create an empty package index so `opkg` doesn't report an error
+	touch $(PKG_BUILD_DIR)/packages/Packages
+	$(INSTALL_DATA) ./files/README.md $(PKG_BUILD_DIR)/packages/
+
 	echo ''                                                        >> $(PKG_BUILD_DIR)/repositories.conf
 	echo '## This is the local package repository, do not remove!' >> $(PKG_BUILD_DIR)/repositories.conf
 	echo 'src imagebuilder file:packages'                          >> $(PKG_BUILD_DIR)/repositories.conf
 
+ifeq ($(CONFIG_BUILDBOT),)
   ifeq ($(CONFIG_IB_STANDALONE),)
 	$(FIND) $(call FeedPackageDir,libc) -type f \
 		\( -name 'libc_*.ipk' -or -name 'kernel_*.ipk' -or -name 'kmod-*.ipk' \) \
diff --git a/target/imagebuilder/files/README.md b/target/imagebuilder/files/README.md
new file mode 100644
index 0000000000..9a9616d06d
--- /dev/null
+++ b/target/imagebuilder/files/README.md
@@ -0,0 +1,11 @@
+# ./packages folder
+
+Add `.ipk` packages to this folder will allow the ImageBuilder to install them.
+
+For more complex setups consider adding a custom feed containing packages.
+
+    src custom file:///path/to/packages
+
+Whenever the ImageBuilder builds a firmware image this folder will be reloaded
+and a new package index created. In case signature checks are enabled the
+`./packages/Packages` index will be signed with a locally generated key pair.