diff --git a/poky/meta/conf/machine/qemuarm64.conf b/poky/meta/conf/machine/qemuarm64.conf
index ffc51c8..2f0f0e4 100644
--- a/poky/meta/conf/machine/qemuarm64.conf
+++ b/poky/meta/conf/machine/qemuarm64.conf
@@ -16,7 +16,7 @@
 QB_SYSTEM_NAME = "qemu-system-aarch64"
 QB_MACHINE = "-machine virt"
 QB_CPU = "-cpu cortex-a57"
-QB_SMP = "-smp 4"
+QB_SMP ?= "-smp 4"
 QB_CPU_KVM = "-cpu host -machine gic-version=3"
 # For graphics to work we need to define the VGA device as well as the necessary USB devices
 QB_GRAPHICS = "-device virtio-gpu-pci"