diff --git a/BOOKSHELF b/BOOKSHELF
index f1b9803..4915474 100644
--- a/BOOKSHELF
+++ b/BOOKSHELF
@@ -20,3 +20,6 @@ D: http://www.ftdichip.com/Support/Documents/AppNotes/AN232R-01_FT232RBitBangMod
 
 N: c2
 D: http://www.silabs.com/Support%20Documents/TechnicalDocs/C2spec.pdf
+
+N: dfu
+D: http://www.usb.org/developers/devclass_docs/DFU_1.1.pdf
diff --git a/f32x/README b/f32x/README
index c8893b0..b4d2ac5 100644
--- a/f32x/README
+++ b/f32x/README
@@ -11,3 +11,9 @@ CLK	3	SPI_CLK0	E13	C2CK	C2D
 MOSI	4	SPI_MOSI0	E12	C2D	-
 MISO	5	SPI_MISO0	E11	-	C2CK
 nSS	6	SS0		G2	-	-
+
+
+On the Ben, the kernel driver has to release the MMC port before it
+can be used by f32x:
+
+echo jz4740-mmc.0 >/sys/bus/platform/drivers/jz4740-mmc/unbind