diff --git a/configs/stm32f4discovery/ostest/defconfig b/configs/stm32f4discovery/ostest/defconfig
index ab7e07aa26e..dd67ea920a8 100755
--- a/configs/stm32f4discovery/ostest/defconfig
+++ b/configs/stm32f4discovery/ostest/defconfig
@@ -872,7 +872,7 @@ CONFIG_PL2303_TXBUFSIZE=512
 #   Default 64
 # CONFIG_CDCACM_EPBULKOUT
 #   The logical 7-bit address of a hardware endpoint that supports
-#   bulk OUT operation
+#   bulk OUT operation.  Default 4.
 # CONFIG_CDCACM_EPBULKOUT_FSSIZE
 #   Max package size for the bulk OUT endpoint if full speed mode.
 #   Default 64.
@@ -881,7 +881,7 @@ CONFIG_PL2303_TXBUFSIZE=512
 #   Default 512.
 # CONFIG_CDCACM_EPBULKIN
 #   The logical 7-bit address of a hardware endpoint that supports
-#   bulk IN operation
+#   bulk IN operation.  Default 3.
 # CONFIG_CDCACM_EPBULKIN_FSSIZE
 #   Max package size for the bulk IN endpoint if full speed mode.
 #   Default 64.
@@ -906,13 +906,13 @@ CONFIG_PL2303_TXBUFSIZE=512
 CONFIG_CDCACM=n
 CONFIG_CDCACM_CONSOLE=n
 #CONFIG_CDCACM_EP0MAXPACKET
-#CONFIG_CDCACM_EPINTIN
+CONFIG_CDCACM_EPINTIN=1
 #CONFIG_CDCACM_EPINTIN_FSSIZE
 #CONFIG_CDCACM_EPINTIN_HSSIZE
-#CONFIG_CDCACM_EPBULKOUT
+CONFIG_CDCACM_EPBULKOUT=3
 #CONFIG_CDCACM_EPBULKOUT_FSSIZE
 #CONFIG_CDCACM_EPBULKOUT_HSSIZE
-#CONFIG_CDCACM_EPBULKIN
+CONFIG_CDCACM_EPBULKIN=2
 #CONFIG_CDCACM_EPBULKIN_FSSIZE
 #CONFIG_CDCACM_EPBULKIN_HSSIZE
 #CONFIG_CDCACM_NWRREQS