diff --git a/GNUmakefile b/GNUmakefile
index 4c84f701..0f75c86c 100755
--- a/GNUmakefile
+++ b/GNUmakefile
@@ -275,9 +275,7 @@ ifeq ($(DETECT_FEATURES),1)
     KECCAK_FLAG = $(SSSE3_FLAG)
     LEA_FLAG = $(SSSE3_FLAG)
     SIMECK_FLAG = $(SSSE3_FLAG)
-    SIMON64_FLAG = $(SSSE3_FLAG)
     SIMON128_FLAG = $(SSSE3_FLAG)
-    SPECK64_FLAG = $(SSSE3_FLAG)
     SPECK128_FLAG = $(SSSE3_FLAG)
     SUN_LDFLAGS += $(SSSE3_FLAG)
   else
diff --git a/GNUmakefile-cross b/GNUmakefile-cross
index c13cd68b..e2435e51 100755
--- a/GNUmakefile-cross
+++ b/GNUmakefile-cross
@@ -227,9 +227,7 @@ ifeq ($(DETECT_FEATURES),1)
     CHAM_FLAG = $(SSSE3_FLAG)
     LEA_FLAG = $(SSSE3_FLAG)
     SIMECK_FLAG = $(SSSE3_FLAG)
-    SIMON64_FLAG = $(SSSE3_FLAG)
     SIMON128_FLAG = $(SSSE3_FLAG)
-    SPECK64_FLAG = $(SSSE3_FLAG)
     SPECK128_FLAG = $(SSSE3_FLAG)
   else
     SSSE3_FLAG =
diff --git a/simon64_simd.cpp b/simon64_simd.cpp
index b14e1c6e..eb5a1757 100644
--- a/simon64_simd.cpp
+++ b/simon64_simd.cpp
@@ -16,13 +16,10 @@
 // #undef CRYPTOPP_SSE41_AVAILABLE
 // #undef CRYPTOPP_ARM_NEON_AVAILABLE
 
-#if (CRYPTOPP_SSSE3_AVAILABLE)
+#if (CRYPTOPP_SSE41_AVAILABLE)
 # include "adv_simd.h"
 # include <pmmintrin.h>
 # include <tmmintrin.h>
-#endif
-
-#if (CRYPTOPP_SSE41_AVAILABLE)
 # include <smmintrin.h>
 #endif
 
@@ -30,11 +27,6 @@
 # include <ammintrin.h>
 #endif
 
-#if defined(__AVX512F__)
-# define CRYPTOPP_AVX512_ROTATE 1
-# include <immintrin.h>
-#endif
-
 // C1189: error: This header is specific to ARM targets
 #if (CRYPTOPP_ARM_NEON_AVAILABLE)
 # include "adv_simd.h"
diff --git a/speck64_simd.cpp b/speck64_simd.cpp
index e6ab4336..0a720fb3 100644
--- a/speck64_simd.cpp
+++ b/speck64_simd.cpp
@@ -16,13 +16,10 @@
 // #undef CRYPTOPP_SSE41_AVAILABLE
 // #undef CRYPTOPP_ARM_NEON_AVAILABLE
 
-#if (CRYPTOPP_SSSE3_AVAILABLE)
+#if (CRYPTOPP_SSE41_AVAILABLE)
 # include "adv_simd.h"
 # include <pmmintrin.h>
 # include <tmmintrin.h>
-#endif
-
-#if (CRYPTOPP_SSE41_AVAILABLE)
 # include <smmintrin.h>
 #endif
 
@@ -30,11 +27,6 @@
 # include <ammintrin.h>
 #endif
 
-#if defined(__AVX512F__)
-# define CRYPTOPP_AVX512_ROTATE 1
-# include <immintrin.h>
-#endif
-
 // C1189: error: This header is specific to ARM targets
 #if (CRYPTOPP_ARM_NEON_AVAILABLE)
 # include "adv_simd.h"