diff --git a/arch/arm/src/stm32f7/chip/stm32f72xx73xx_pinmap.h b/arch/arm/src/stm32f7/chip/stm32f72xx73xx_pinmap.h
index 9e3f10b6be..1f6b927f48 100644
--- a/arch/arm/src/stm32f7/chip/stm32f72xx73xx_pinmap.h
+++ b/arch/arm/src/stm32f7/chip/stm32f72xx73xx_pinmap.h
@@ -576,9 +576,14 @@
 #define GPIO_SAI2_SD_B_3      (GPIO_ALT|GPIO_AF10|GPIO_PORTF|GPIO_PIN11)
 #define GPIO_SAI2_SD_B_4      (GPIO_ALT|GPIO_AF10|GPIO_PORTG|GPIO_PIN10)
 
-/* SD/MMC */
+/* SD/MMC
+ *
+ * Note that the below configures GPIO_SPEED_50MHz I/O, that means for using 
+ * the SDMMC, the board's boot code must enable I/O Compensation in the
+ * SYSCFG_CMPCR register.
+ */
 
-#define GPIO_SDMMC1_CK        (GPIO_ALT|GPIO_AF12|GPIO_PORTC|GPIO_PIN12)
+#define GPIO_SDMMC1_CK        (GPIO_ALT|GPIO_AF12|GPIO_SPEED_50MHz|GPIO_PORTC|GPIO_PIN12)
 #define GPIO_SDMMC1_CMD       (GPIO_ALT|GPIO_AF12|GPIO_PULLUP|GPIO_SPEED_50MHz|GPIO_PUSHPULL|GPIO_PORTD|GPIO_PIN2)
 #define GPIO_SDMMC1_D0        (GPIO_ALT|GPIO_AF12|GPIO_PULLUP|GPIO_SPEED_50MHz|GPIO_PUSHPULL|GPIO_PORTC|GPIO_PIN8)
 #define GPIO_SDMMC1_D1        (GPIO_ALT|GPIO_AF12|GPIO_PULLUP|GPIO_SPEED_50MHz|GPIO_PUSHPULL|GPIO_PORTC|GPIO_PIN9)
diff --git a/configs/sama5d4-ek/README.txt b/configs/sama5d4-ek/README.txt
index 62a88e0860..f4c8a98d79 100644
--- a/configs/sama5d4-ek/README.txt
+++ b/configs/sama5d4-ek/README.txt
@@ -3935,7 +3935,7 @@ Configurations
 
       2014-8-29: System call interface verified.
       2014-9-16: Reverified after fixing changes for the knsh configuration
-                 that broke this on.  All seems to be well now.
+                 that broke this one.  All seems to be well now.
 
   ipv6:
   ----
@@ -4275,6 +4275,13 @@ Configurations
        table, but I am currently stuck in the 'make import' step.  This
        currently dies with a mysterious error '/bin/sh: -w: invalid option'
 
+       That mysterious error is comming from the COMPILE macro defined in
+       apps/import/Make.defs.  There is something lethal about CFLAGS.
+       Although I can print all of the components of CFLAGS, the use of
+       CFLAGS causes the error.  In fact, this will generate the same error;
+
+         $(warning CFLAGS=$(CFLAGS))
+
   nsh:
 
     This configuration directory provide the NuttShell (NSH).  This is a