diff --git a/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf b/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf
index 0f7ff62640..d53b6f57b7 100644
--- a/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf
+++ b/scripts/lib/bsp/substrate/target/arch/qemu/conf/machine/{{=machine}}.conf
@@ -31,13 +31,14 @@ require conf/machine/include/qemu.inc
 require conf/machine/include/tune-i586.inc
 {{ if qemuarch == "x86_64": }}
 require conf/machine/include/qemu.inc
-require conf/machine/include/tune-x86_64.inc
+DEFAULTTUNE ?= "core2-64"
+require conf/machine/include/tune-core2.inc
 {{ if qemuarch == "arm": }}
 require conf/machine/include/qemu.inc
 require conf/machine/include/tune-arm926ejs.inc
 {{ if qemuarch == "powerpc": }}
 require conf/machine/include/qemu.inc
-require conf/machine/include/tune-ppc603e.inc
+require conf/machine/include/tune-ppc7400.inc
 {{ if qemuarch == "mips": }}
 require conf/machine/include/qemu.inc
 require conf/machine/include/tune-mips32.inc