diff --git a/quickemu b/quickemu
index d600408..d5ededf 100755
--- a/quickemu
+++ b/quickemu
@@ -489,7 +489,7 @@ function vm_boot() {
   fi
 
   # Determine a sane resolution for Linux guests.
-  if [ "${guest}" == "linux" ]; then
+  if [ "${guest_os}" == "linux" ]; then
     local X_RES=1152
     local Y_RES=648
     if [ "${XDG_SESSION_TYPE}" == "x11" ]; then