diff --git a/hal/halx86/generic/halinit.c b/hal/halx86/generic/halinit.c
index 62213f244531d..bffeb933c79cc 100644
--- a/hal/halx86/generic/halinit.c
+++ b/hal/halx86/generic/halinit.c
@@ -14,6 +14,9 @@
 
 /* GLOBALS *******************************************************************/
 
+#ifdef CONFIG_SMP
+BOOLEAN HalpOnlyBootProcessor;
+#endif
 BOOLEAN HalpPciLockSettings;
 
 /* PRIVATE FUNCTIONS *********************************************************/
@@ -30,6 +33,12 @@ HalpGetParameters(
         /* Read the command line */
         PCSTR CommandLine = LoaderBlock->LoadOptions;
 
+#ifdef CONFIG_SMP
+        /* Check whether we should only start one CPU */
+        if (strstr(CommandLine, "ONECPU"))
+            HalpOnlyBootProcessor = TRUE;
+#endif
+
         /* Check if PCI is locked */
         if (strstr(CommandLine, "PCILOCK"))
             HalpPciLockSettings = TRUE;
diff --git a/hal/halx86/smp/i386/spinup.c b/hal/halx86/smp/i386/spinup.c
index 12fbea168cb35..359cc30d657d0 100644
--- a/hal/halx86/smp/i386/spinup.c
+++ b/hal/halx86/smp/i386/spinup.c
@@ -16,6 +16,8 @@
 
 /* GLOBALS *******************************************************************/
 
+extern BOOLEAN HalpOnlyBootProcessor;
+
 extern PPROCESSOR_IDENTITY HalpProcessorIdentity;
 extern PHYSICAL_ADDRESS HalpLowStubPhysicalAddress;
 extern PVOID HalpLowStub;
@@ -88,6 +90,11 @@ HalStartNextProcessor(
     _In_ PLOADER_PARAMETER_BLOCK LoaderBlock,
     _In_ PKPROCESSOR_STATE ProcessorState)
 {
+    /* Bail out if we only use the boot CPU */
+    if (HalpOnlyBootProcessor)
+        return FALSE;
+
+    /* Bail out if we have started all available CPUs */
     if (HalpStartedProcessorCount == HalpApicInfoTable.ProcessorCount)
         return FALSE;