diff --git a/openbios-devel/config/scripts/switch-arch b/openbios-devel/config/scripts/switch-arch
index 38d263d..9e7d0fd 100755
--- a/openbios-devel/config/scripts/switch-arch
+++ b/openbios-devel/config/scripts/switch-arch
@@ -265,7 +265,7 @@ for ARCH in $arch_list; do
         ppc)
         select_prefix powerpc powerpc64
         if [ "$unix" = "no" ]; then
-            CFLAGS="-m32 -msoft-float -fno-builtin-bcopy -fno-builtin-log2"
+            CFLAGS="-m32 -mcpu=602 -msoft-float -fno-builtin-bcopy -fno-builtin-log2"
             AS_FLAGS="-m32"
         else
             CFLAGS="-fno-builtin"
@@ -275,7 +275,7 @@ for ARCH in $arch_list; do
 
         ppc64)
         select_prefix powerpc64
-        CFLAGS="-Wa,-a64 -m64 -msoft-float -fno-builtin"
+        CFLAGS="-Wa,-a64 -m64 -mcpu=G5 -msoft-float -fno-builtin"
         AS_FLAGS="-Wa,-a64"
         ;;