diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 48f1866c33..e589fac759 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -3168,3 +3168,5 @@
 	  serial.c.
 	* arch/arm/src/stm32/stm32_spi.c:  SPI driver can now survice re-
 	  initialization (Mike Smith).
+	* tools/mkconfig.c:  If CONFIG_DRAM_END is not specified, this tool
+	  will provide default definition of (CONFIG_DRAM_START + CONFIG_DRAM_SIZE)
diff --git a/nuttx/Makefile b/nuttx/Makefile
index ea83d69ee2..b0a17efd25 100644
--- a/nuttx/Makefile
+++ b/nuttx/Makefile
@@ -276,8 +276,8 @@ include/stdarg.h:
 endif
 
 # Targets used to build include/nuttx/version.h.  Creation of version.h is
-# part of the overall NuttX configuration sequency.  Notice that the
-# tools/mkversion tool is cuilt and used to create include/nuttx/version.h
+# part of the overall NuttX configuration sequence. Notice that the
+# tools/mkversion tool is built and used to create include/nuttx/version.h
 
 tools/mkversion:
 	@$(MAKE) -C tools -f Makefile.host TOPDIR="$(TOPDIR)"  mkversion
@@ -293,8 +293,8 @@ include/nuttx/version.h: $(TOPDIR)/.version tools/mkversion
 	@tools/mkversion $(TOPDIR) > include/nuttx/version.h
 
 # Targets used to build include/nuttx/config.h.  Creation of config.h is
-# part of the overall NuttX configuration sequency.  Notice that the
-# tools/mkconfig tool is cuilt and used to create include/nuttx/config.h
+# part of the overall NuttX configuration sequence. Notice that the
+# tools/mkconfig tool is built and used to create include/nuttx/config.h
 
 tools/mkconfig:
 	@$(MAKE) -C tools -f Makefile.host TOPDIR="$(TOPDIR)"  mkconfig
diff --git a/nuttx/tools/mkconfig.c b/nuttx/tools/mkconfig.c
index 97e2a9c34c..b3749266c1 100644
--- a/nuttx/tools/mkconfig.c
+++ b/nuttx/tools/mkconfig.c
@@ -174,6 +174,12 @@ int main(int argc, char **argv, char **envp)
   printf("#ifndef CONFIG_MM_REGIONS\n");
   printf("# define CONFIG_MM_REGIONS 1\n");
   printf("#endif\n\n");
+  printf("/* If the end of RAM is not specified then it is assumed to be the beginning\n");
+  printf(" * of RAM plus the RAM size.\n");
+  printf(" */\n\n");
+  printf("#ifndef CONFIG_DRAM_END\n");
+  printf("# define CONFIG_DRAM_END (CONFIG_DRAM_START+CONFIG_DRAM_SIZE)\n");
+  printf("#endif\n\n");
   printf("/* If no file streams are configured, then make certain that buffered I/O\n");
   printf(" * support is disabled\n");
   printf(" */\n\n");
@@ -256,6 +262,7 @@ int main(int argc, char **argv, char **envp)
   printf("# undef CONFIG_DEBUG_USB\n");
   printf("# undef CONFIG_DEBUG_GRAPHICS\n");
   printf("# undef CONFIG_DEBUG_GPIO\n");
+  printf("# undef CONFIG_DEBUG_SPI\n");
   printf("# undef CONFIG_DEBUG_STACK\n");
   printf("#endif\n\n");
   printf("#endif /* __INCLUDE_NUTTX_CONFIG_H */\n");