diff --git a/configs/metro-m4/include/board.h b/configs/metro-m4/include/board.h
index daeeafc85c..42c760b2c8 100644
--- a/configs/metro-m4/include/board.h
+++ b/configs/metro-m4/include/board.h
@@ -148,7 +148,6 @@
 #define BOARD_GCLK_SET2         0x0fdf    /* Post-configure: All GCLKs except GCLK5 */
 
 #define BOARD_GCLK0_ENABLE      TRUE      /* Enable GCLK0 */
-#define BOARD_GCLK0_IDC         FALSE     /* Don't improve duty cycle */
 #define BOARD_GCLK0_OOV         FALSE     /* Clock output will be LOW */
 #define BOARD_GCLK0_OE          TRUE      /* Generate output on GCLK_IO */
 #define BOARD_GCLK0_DIVSEL      0         /* GCLK frequency is source/DIV */
@@ -403,7 +402,7 @@
  * before using the SERCOM.
  */
 
-#define BOARD_SERCOM_SLOWGEN         3                   /* 48MHz, common to all SERCOMS */
+#define BOARD_SERCOM_SLOWGEN         3                   /* 32.768KHz, common to all SERCOMS */
 #define BOARD_SERCOM_SLOWLOCK        FALSE               /* Don't lock the SLOWCLOCK */
 #define BOARD_SLOWCLOCK_FREQUENCY    BOARD_GCLK3_FREQUENCY
 
diff --git a/configs/olimex-stm32-p407/README.txt b/configs/olimex-stm32-p407/README.txt
index be2528927b..9b2593a967 100644
--- a/configs/olimex-stm32-p407/README.txt
+++ b/configs/olimex-stm32-p407/README.txt
@@ -374,6 +374,16 @@ Configuration sub-directories
 The <subdir> that is provided above as an argument to the tools/configure.sh
 must be is one of the following.
 
+  dhtxx:
+
+    Configuration added by Abdelatif Guettouche for testing the the DHTxx
+    sensor.  This configuration expects this setup:
+
+      DHTXX_PIN_OUTPUT   PG9
+      DHTXX_PIN_INPUT    PG9
+
+    The STM32 free-running timer is also required.
+
   kelf:
 
     This is a protected mode version of the apps/examples/elf test of
diff --git a/configs/olimex-stm32-p407/src/olimex-stm32-p407.h b/configs/olimex-stm32-p407/src/olimex-stm32-p407.h
index 622adf0a1d..be946f2904 100644
--- a/configs/olimex-stm32-p407/src/olimex-stm32-p407.h
+++ b/configs/olimex-stm32-p407/src/olimex-stm32-p407.h
@@ -169,7 +169,7 @@
 #define GPIO_BTN_DOWN     (GPIO_INPUT|GPIO_FLOAT|GPIO_EXTI|GPIO_PORTG|GPIO_PIN8)
 #define GPIO_BTN_CENTER   (GPIO_INPUT|GPIO_FLOAT|GPIO_EXTI|GPIO_PORTG|GPIO_PIN15)
 
-/* DHTxx confing pin. */
+/* DHTxx pin configuration */
 
 #define GPIO_DHTXX_PIN          (GPIO_PORTG|GPIO_PIN9)
 #define GPIO_DHTXX_PIN_OUTPUT   (GPIO_OUTPUT|GPIO_FLOAT|GPIO_SPEED_100MHz|GPIO_DHTXX_PIN)