diff --git a/meta/conf/machine/include/x86/qemuboot-x86.inc b/meta/conf/machine/include/x86/qemuboot-x86.inc
index 82ef4a0b73..3234e8cbf0 100644
--- a/meta/conf/machine/include/x86/qemuboot-x86.inc
+++ b/meta/conf/machine/include/x86/qemuboot-x86.inc
@@ -7,7 +7,7 @@ QB_CPU_KVM:x86 ?= "-cpu IvyBridge -machine q35,i8042=off"
 QB_CPU:x86-64 ?= "-cpu Skylake-Client -machine q35,i8042=off"
 QB_CPU_KVM:x86-64 ?= "-cpu Skylake-Client -machine q35,i8042=off"
 
-QB_AUDIO_DRV = "alsa"
-QB_AUDIO_OPT = "-device AC97"
+QB_AUDIO_DRV ?= "alsa"
+QB_AUDIO_OPT ?= "-device AC97"
 QB_KERNEL_CMDLINE_APPEND = "oprofile.timer=1 tsc=reliable no_timer_check rcupdate.rcu_expedited=1"
 QB_OPT_APPEND = "-usb -device usb-tablet -usb -device usb-kbd"