diff --git a/src/boot.sh b/src/boot.sh
index 2ecf50a..1fb847b 100644
--- a/src/boot.sh
+++ b/src/boot.sh
@@ -100,11 +100,16 @@ else
 fi
 
 SM_BIOS=""
-BIOS_SERIAL=$(</sys/class/dmi/id/product_serial)
-BIOS_SERIAL="${BIOS_SERIAL//[![:alnum:]]/}"
 
-if [ -n "$BIOS_SERIAL" ]; then
-  SM_BIOS="-smbios type=1,serial=$BIOS_SERIAL"
+if [ -s "/sys/class/dmi/id/product_serial" ]; then
+
+  BIOS_SERIAL=$(</sys/class/dmi/id/product_serial)
+  BIOS_SERIAL="${BIOS_SERIAL//[![:alnum:]]/}"
+
+  if [ -n "$BIOS_SERIAL" ]; then
+    SM_BIOS="-smbios type=1,serial=$BIOS_SERIAL"
+  fi
+
 fi
 
 return 0