diff --git a/src/boot.sh b/src/boot.sh
index e3735f8..c709f7d 100644
--- a/src/boot.sh
+++ b/src/boot.sh
@@ -167,6 +167,7 @@ else
   CPU_FLAGS="$DEFAULT_FLAGS,$CPU_FLAGS"
 fi
 
+SM_BIOS=""
 CLOCKSOURCE="tsc"
 [[ "${ARCH,,}" == "arm64" ]] && CLOCKSOURCE="arch_sys_counter"
 CLOCK="/sys/devices/system/clocksource/clocksource0/current_clocksource"