diff --git a/README b/README
index 056b717..3496bef 100644
--- a/README
+++ b/README
@@ -646,35 +646,6 @@
 		which adds regex support to some commands, as for
 		example "env grep" and "setexpr".
 
-- Device tree:
-		CONFIG_OF_CONTROL
-		If this variable is defined, U-Boot will use a device tree
-		to configure its devices, instead of relying on statically
-		compiled #defines in the board file. This option is
-		experimental and only available on a few boards. The device
-		tree is available in the global data as gd->fdt_blob.
-
-		U-Boot needs to get its device tree from somewhere. This can
-		be done using one of the three options below:
-
-		CONFIG_OF_SEPARATE
-		If this variable is defined, U-Boot will build a device tree
-		binary. It will be called u-boot.dtb. Architecture-specific
-		code will locate it at run-time. Generally this works by:
-
-			cat u-boot.bin u-boot.dtb >image.bin
-
-		and in fact, U-Boot does this for you, creating a file called
-		u-boot-dtb.bin which is useful in the common case. You can
-		still use the individual files if you need something more
-		exotic.
-
-		CONFIG_OF_BOARD
-		If this variable is defined, U-Boot will use the device tree
-		provided by the board at runtime instead of embedding one with
-		the image. Only boards defining board_fdt_blob_setup() support
-		this option (see include/fdtdec.h file).
-
 - Watchdog:
 		CONFIG_WATCHDOG
 		If this variable is defined, it enables watchdog
diff --git a/dts/Kconfig b/dts/Kconfig
index 5dcc79d..e57ce84 100644
--- a/dts/Kconfig
+++ b/dts/Kconfig
@@ -98,13 +98,36 @@
 
 config OF_BOARD
 	bool "Provided by the board (e.g a previous loader) at runtime"
-	default y if SANDBOX
+	default y if SANDBOX || OF_HAS_PRIOR_STAGE
 	help
-	  If this option is enabled, the device tree will be provided by
-	  the board at runtime if the board supports it. The device tree bundled
-	  with the image (if any) will be overridden / ignored.
+	  If this option is enabled, the device tree is provided at runtime by
+	  a custom function called board_fdt_blob_setup(). The board must
+	  implement this function if it wishes to provide special behaviour.
 
-	  A device tree file must be provided in the tree.
+	  With this option, the device tree build by U-Boot may be overridden or
+	  ignored. See OF_HAS_PRIOR_STAGE.
+
+	  Note: Boards which use this to handle a device tree passed from an
+	  earlier stage should enable OF_HAS_PRIOR_STAGE.
+
+config OF_HAS_PRIOR_STAGE
+	bool
+	help
+	  Indicates that a prior stage of the firmware (before U-Boot proper)
+	  makes use of device tree and this board normally boots with that prior
+	  stage, that provides a devicetree to U-Boot.
+
+	  This means that the device tree built in U-Boot should not be packaged
+	  in the firmware image. Instead, the prior stage's device tree should
+	  be so packaged. At runtime, the prior stage reads this, does any
+	  necessary fix-ups, then passes it to U-Boot. See OF_BOARD.
+
+	  This option does not preclude using the U-Boot device tree, e.g. for
+	  development purposes, but it is not recommended, and likely will not
+	  even work, for production systems.
+
+	  Note: This option must be set in Kconfig and cannot be enabled or
+	  disabled in the board's defconfig file.
 
 config DEFAULT_DEVICE_TREE
 	string "Default Device Tree for DT control"
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index 118c100..280cda6 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -1595,6 +1595,7 @@
 	return 0;
 }
 
+/* TODO(sjg@chromium.org): This function should not be weak */
 __weak int fdtdec_board_setup(const void *fdt_blob)
 {
 	return 0;