diff --git a/CMakeLists.txt b/CMakeLists.txt
index cdabc9660..a87d5b5df 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -466,10 +466,10 @@ if("Ninja" STREQUAL ${CMAKE_GENERATOR})
 endif()
 
 # Add -Werror to C/C++ flags for newer compilers
-#if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9)
-#  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
-#  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
-#endif()
+if(NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.9)
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Werror")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
+endif()
 
 message(STATUS "CMAKE_C_FLAGS is ${CMAKE_C_FLAGS}")
 message(STATUS "CMAKE_CXX_FLAGS is ${CMAKE_CXX_FLAGS}")
diff --git a/lib/include/srslte/phy/utils/simd.h b/lib/include/srslte/phy/utils/simd.h
index 024de72e4..a1b797686 100644
--- a/lib/include/srslte/phy/utils/simd.h
+++ b/lib/include/srslte/phy/utils/simd.h
@@ -1560,7 +1560,7 @@ static inline simd_s_t srslte_simd_s_neg(simd_s_t a, simd_s_t b)
   // -a
   int16x8_t neg = vnegq_s16(a);
   // bitwise select either a or neg based on ltMask
-  int16x8_t masked = vbslq_s16(ltMask, a, neg);
+  int16x8_t masked = vbslq_s16(ltMask, neg, a);
   // res = masked & (~zeroMask)
   int16x8_t res = vbicq_s16(masked, zeroMask);
   return res;
@@ -2074,7 +2074,7 @@ static inline simd_b_t srslte_simd_b_neg(simd_b_t a, simd_b_t b)
   // -a
   int8x16_t neg = vnegq_s8(a);
   // bitwise select either a or neg based on ltMask
-  int8x16_t masked = vbslq_s8(ltMask, a, neg);
+  int8x16_t masked = vbslq_s8(ltMask, neg, a);
   // res = masked & (~zeroMask)
   int8x16_t res = vbicq_s8(masked, zeroMask);
   return res;