diff --git a/devices/video/atimach64gx.cpp b/devices/video/atimach64gx.cpp
index a9bea61..e6cab6d 100644
--- a/devices/video/atimach64gx.cpp
+++ b/devices/video/atimach64gx.cpp
@@ -688,7 +688,7 @@ void AtiMach64Gx::crtc_update()
 
     uint32_t new_vert_blank = new_vtotal - new_height;
     if (new_vert_blank != this->vert_blank) {
-        this->vert_blank = vert_blank;
+        this->vert_blank = new_vert_blank;
         need_recalc = true;
     }
 
diff --git a/devices/video/atirage.cpp b/devices/video/atirage.cpp
index 57fe2e5..14d88a2 100644
--- a/devices/video/atirage.cpp
+++ b/devices/video/atirage.cpp
@@ -724,7 +724,7 @@ void ATIRage::crtc_update() {
 
     uint32_t new_vert_blank = new_vtotal - new_height;
     if (new_vert_blank != this->vert_blank) {
-        this->vert_blank = vert_blank;
+        this->vert_blank = new_vert_blank;
         need_recalc = true;
     }