diff --git a/src/stub/src/arch/amd64/macros.S b/src/stub/src/arch/amd64/macros.S
index 371d8cc7..451b95a4 100644
--- a/src/stub/src/arch/amd64/macros.S
+++ b/src/stub/src/arch/amd64/macros.S
@@ -27,7 +27,13 @@
 ;
 */
 
-                //.altmacro
+#undef amd64
+#undef i386
+#undef i486
+#undef i586
+#undef x86_64
+
+                //.altmacro       // not supported by x86_64-linux-as
                 .code64
 
 .macro          section name
diff --git a/src/stub/src/arch/i086/macros.S b/src/stub/src/arch/i086/macros.S
index e088cbe4..aed98c00 100644
--- a/src/stub/src/arch/i086/macros.S
+++ b/src/stub/src/arch/i086/macros.S
@@ -27,8 +27,15 @@
 ;
 */
 
+#undef amd64
+#undef i386
+#undef i486
+#undef i586
+#undef x86_64
+
                 .altmacro
                 .intel_syntax noprefix
+                .arch   i8086, nojumps
                 .code16
 
 .macro          section name
diff --git a/src/stub/src/arch/i386/macros.S b/src/stub/src/arch/i386/macros.S
index b04f5668..9bf61a05 100644
--- a/src/stub/src/arch/i386/macros.S
+++ b/src/stub/src/arch/i386/macros.S
@@ -27,8 +27,16 @@
 ;
 */
 
+#undef amd64
+#undef i386
+#undef i486
+#undef i586
+#undef x86_64
+
                 .altmacro
                 .intel_syntax noprefix
+                // FIXME: enabing this causes stub changes ???
+                //.arch   i386, nojumps
                 .code32
 
 .macro          section name
@@ -38,6 +46,7 @@
 
 .macro          CPU     id
                 .ifc    \id, 386
+                // FIXME: enabing this causes stub changes ???
                 //.arch   i386, nojumps
                 .endif
                 .ifc    \id, 486