diff --git a/dist/buildmk b/dist/buildmk
index 2fe14ccf..cee62ba6 100755
--- a/dist/buildmk
+++ b/dist/buildmk
@@ -2,17 +2,16 @@
 
 # run this in the src directory
 SYSNAME=`uname` export SYSNAME
-OBJTYPE=`uname -p | sed '
-	s;i.86;386;;
-	s;i86pc;386;;
-	s;amd64;x86_64;;
-	s;/.*;;; s; ;;g;
-	s;armv.*;arm;g;
-	s;powerpc;power;g;
-	s;PowerMacintosh;power;g;
-	s;macppc;power;g;
-	s;ppc64;power;g;
-	s;ppc;power;g;
+OBJTYPE=`uname -m -p | sed '
+	s;.*i[3-6]86.*;386;;
+	s;.*i86pc.*;386;;
+	s;.*amd64.*;x86_64;;
+	s;.*x86_64.*;x86_64;;
+	s;.*armv.*;arm;g;
+	s;.*powerpc.*;power;g;
+	s;.*PowerMacintosh.*;power;g;
+	s;.*macppc.*;power;g;
+	s;.*ppc64.*;power;g;
+	s;.*ppc.*;power;g;
 '` export OBJTYPE
 sh -x mkmk.sh
-
diff --git a/src/mkhdr b/src/mkhdr
index 1fc37ebd..fdc9c447 100644
--- a/src/mkhdr
+++ b/src/mkhdr
@@ -1,16 +1,16 @@
 # if you change this, also edit ../dist/buildmk
 SYSNAME=`uname`
-OBJTYPE=`uname -p | sed '
-	s;i.86;386;;
-	s;i86pc;386;;
-	s;amd64;x86_64;;
-	s;/.*;;; s; ;;g;
-	s;armv.*;arm;g;
-	s;powerpc;power;g;
-	s;PowerMacintosh;power;g;
-	s;macppc;power;g;
-	s;ppc64;power;g;
-	s;ppc;power;g;
+OBJTYPE=`uname -m -p | sed '
+	s;.*i[3-6]86.*;386;;
+	s;.*i86pc.*;386;;
+	s;.*amd64.*;x86_64;;
+	s;.*x86_64.*;x86_64;;
+	s;.*armv.*;arm;g;
+	s;.*powerpc.*;power;g;
+	s;.*PowerMacintosh.*;power;g;
+	s;.*macppc.*;power;g;
+	s;.*ppc64.*;power;g;
+	s;.*ppc.*;power;g;
 '`
 
 BIN=$PLAN9/bin