--- a/src/app/virtualbox/src/VBox/Devices/PC/vbox-cpuhotplug.dsl
+++ b/src/app/virtualbox/src/VBox/Devices/PC/vbox-cpuhotplug.dsl
@@ -27,6 +27,18 @@
         Return(LEqual(CPUL, 0x01))
     }
 
+    // Method to notify the VMM that a CPU is not
+    // in use anymore and can be safely removed.
+    // Using the extra method here because the CPUL
+    // register identifer clashes with the CPUL object defined
+    // below making iasl starting with version 20150930 fail.
+    //
+    // Think of CPLO as "CPU Lock Open"
+    Method(CPLO, 1)
+    {
+        Store (Arg0, CPUL)
+    }
+
     Scope (\_SB)
     {
 
@@ -73,7 +85,7 @@
             }                                                              \
             Method(_EJ0, 1)                                                \
             {                                                              \
-                Store(id, CPUL) /* Unlock the CPU */                       \
+                CPLO(id) /* Unlock the CPU */                              \
                 Return                                                     \
             }                                                              \
         }                                                                  \
