diff --git a/configure.ac b/configure.ac
index c5a6c76..b6f6063 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,4 +1,4 @@
-AC_INIT([merit-miner], [0.1.0])
+AC_INIT([merit-miner], [0.2.0])
 
 AC_PREREQ([2.59c])
 AC_CANONICAL_SYSTEM
@@ -76,18 +76,20 @@ fi
 AC_ARG_ENABLE([march],
     [AS_HELP_STRING([--enable-march], [Use native CPU instructions for mining (default is no)])],
     [enable_march=$enableval],
-    [enable_march=no])
+    [enable_march=yes])
 
 CFLAGS="$CFLAGS -O3"
 
-AC_MSG_CHECKING(whether we can compile with native arch for AVX2 support)
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,[ _mm256_broadcastq_epi64(_mm_cvtsi64_si128(0xff)); ])],
-  CXXFLAGS="$CXXFLAGS -march=native"
-  AC_MSG_RESULT(yes)
-,
-  AC_MSG_RESULT(no)
-  AC_MSG_WARN([The assembler does not support the AVX2 instruction set.])
-)
+if test x$enable_march != xno; then
+  AC_MSG_CHECKING(whether we can compile with native arch for AVX2 support)
+  AC_COMPILE_IFELSE([AC_LANG_PROGRAM(,[ _mm256_broadcastq_epi64(_mm_cvtsi64_si128(0xff)); ])],
+    CXXFLAGS="$CXXFLAGS -march=native"
+    AC_MSG_RESULT(yes)
+  ,
+    AC_MSG_RESULT(no)
+    AC_MSG_WARN([The assembler does not support the AVX2 instruction set.])
+  )
+fi
 
 if test x$enable_assembly == xyes -a x$have_x86_64 = xtrue
 then
diff --git a/util.c b/util.c
index 9065bce..06cf0a0 100644
--- a/util.c
+++ b/util.c
@@ -769,7 +769,7 @@ void diff_to_target(uint32_t *target, double diff)
 
 	for (k = 7; k > 0 && diff > 1.0; k--)
 		diff /= 4294967296.0;
-	m = 4294901760.0 / diff;
+	m = 2147450880.0 / diff;
 
 	memset(target, 0, 32);
 	target[k] = (uint32_t)m;