diff --git a/hermit/arch/x86/kernel/apic.c b/hermit/arch/x86/kernel/apic.c
index f73ee7707..02af40d11 100644
--- a/hermit/arch/x86/kernel/apic.c
+++ b/hermit/arch/x86/kernel/apic.c
@@ -51,6 +51,7 @@ extern const void kernel_start;
 
 #define IOAPIC_ADDR	((size_t) &kernel_start - 2*PAGE_SIZE)
 #define LAPIC_ADDR	((size_t) &kernel_start - 1*PAGE_SIZE)
+#define MAX_APIC_CORES	256
 
 // IO APIC MMIO structure: write reg, then read or write data.
 typedef struct {
@@ -59,7 +60,7 @@ typedef struct {
 	uint32_t data;
 } ioapic_t;
 
-static const apic_processor_entry_t* apic_processors[MAX_CORES] = {[0 ... MAX_CORES-1] = NULL};
+static const apic_processor_entry_t* apic_processors[MAX_APIC_CORES] = {[0 ... MAX_APIC_CORES-1] = NULL};
 extern int32_t boot_processor;
 extern uint32_t cpu_freq;
 apic_mp_t* apic_mp  __attribute__ ((section (".data"))) = NULL;
@@ -70,7 +71,7 @@ static uint32_t icr = 0;
 static uint32_t ncores = 1;
 static uint8_t irq_redirect[16] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0xA, 0xB, 0xC, 0xD, 0xE, 0xF};
 static uint8_t initialized = 0;
-static uint8_t online[MAX_CORES] = {[0 ... MAX_CORES-1] = 0};
+static uint8_t online[MAX_APIC_CORES] = {[0 ... MAX_APIC_CORES-1] = 0};
 
 spinlock_t bootlock = SPINLOCK_INIT;
 
@@ -469,7 +470,7 @@ found_mp:
 		if (*((uint8_t*) addr) == 0) { // cpu entry
 			apic_processor_entry_t* cpu = (apic_processor_entry_t*) addr;
 
-			if (j < MAX_CORES) {
+			if (j < MAX_APIC_CORES) {
 				 // is the processor usable?
 				if (cpu->cpu_flags & 0x01) {
 					apic_processors[j] = cpu;
@@ -564,6 +565,7 @@ extern int smp_main(void);
 extern void gdt_flush(void);
 extern int set_idle_task(void);
 
+#if MAX_CORES > 1
 int smp_start(void)
 {
 	if (lapic && has_x2apic()) // enable x2APIC support
@@ -599,7 +601,6 @@ int smp_start(void)
 	return smp_main();
 }
 
-#if MAX_CORES > 1
 static inline void set_ipi_dest(uint32_t cpu_id) {
 	uint32_t tmp;
 
@@ -624,7 +625,7 @@ int ipi_tlb_flush(void)
 	}
 
 	flags = irq_nested_disable();
-	for(i=0; i<MAX_CORES; i++)
+	for(i=0; i<MAX_APIC_CORES; i++)
 	{
 		if (i == core_id)
 			continue;
diff --git a/hermit/arch/x86/kernel/entry.asm b/hermit/arch/x86/kernel/entry.asm
index e0c1e3d3f..7d450174a 100644
--- a/hermit/arch/x86/kernel/entry.asm
+++ b/hermit/arch/x86/kernel/entry.asm
@@ -343,9 +343,11 @@ start64:
     xor rdi, rdi
 
 Lno_unmap:
+%if MAX_CORES > 1
     mov eax, DWORD [cpu_online]
     cmp eax, 0
     jne Lsmp_main
+%endif
 
     ; set default stack pointer
     mov rsp, boot_stack
@@ -364,6 +366,7 @@ L1:
     call main
     jmp $
 
+%if MAX_CORES > 1
 Lsmp_main:
     ; dirty to hack to determine the cpu id
     ; with a temporary stack
@@ -385,6 +388,7 @@ Lsmp_main:
     DQ 0, 0, 0, 0
     DQ 0, 0, 0, 0
 tmp_stack:
+%endif
 
 global gdt_flush
 extern gp
diff --git a/hermit/arch/x86/kernel/processor.c b/hermit/arch/x86/kernel/processor.c
index e2ec26f5b..9da65458d 100644
--- a/hermit/arch/x86/kernel/processor.c
+++ b/hermit/arch/x86/kernel/processor.c
@@ -235,13 +235,19 @@ int cpu_detection(void) {
 		wrmsr(MSR_EFER, rdmsr(MSR_EFER) | EFER_NXE);
 
 	wrmsr(MSR_FS_BASE, 0);
+#if MAX_CORES > 1
 	wrmsr(MSR_GS_BASE, apic_cpu_id() * ((size_t) &percore_end0 - (size_t) &percore_start));
+#else
+	wrmsr(MSR_GS_BASE, 0);
+#endif
 	wrmsr(MSR_KERNEL_GS_BASE, 0);
 
 	kprintf("Core %d set per_core offset to 0x%x\n", apic_cpu_id(), rdmsr(MSR_GS_BASE));
 
+#if MAX_CORES > 1
 	/* set core id to apic_cpu_id */
 	set_per_core(__core_id, apic_cpu_id());
+#endif
 
 	if (first_time && has_sse())
 		wmb = sfence;
diff --git a/hermit/include/hermit/stddef.h b/hermit/include/hermit/stddef.h
index 0d4c460f1..9edecfbb0 100644
--- a/hermit/include/hermit/stddef.h
+++ b/hermit/include/hermit/stddef.h
@@ -58,10 +58,13 @@ DECLARE_PER_CORE(struct task*, current_task);
 /* allows fast access to the kernel stack */
 DECLARE_PER_CORE(char*, kernel_stack);
 
+#if MAX_CORES > 1
 /* allows fast access to the core id */
 DECLARE_PER_CORE(uint32_t, __core_id);
-
 #define CORE_ID per_core(__core_id)
+#else
+#define CORE_ID 0
+#endif
 
 #ifdef __cplusplus
 }
diff --git a/hermit/kernel/main.c b/hermit/kernel/main.c
index 4cf1dd97d..5936992c4 100644
--- a/hermit/kernel/main.c
+++ b/hermit/kernel/main.c
@@ -94,6 +94,7 @@ static int hermit_init(void)
 	return 0;
 }
 
+#if MAX_CORES > 1
 int smp_main(void)
 {
 	int32_t cpu = atomic_int32_inc(&cpu_online);
@@ -109,6 +110,7 @@ int smp_main(void)
 
 	return 0;
 }
+#endif
 
 // init task => creates all other tasks an initialize the LwIP
 static int initd(void* arg)
diff --git a/hermit/kernel/tasks.c b/hermit/kernel/tasks.c
index 97471f516..328f28ebc 100644
--- a/hermit/kernel/tasks.c
+++ b/hermit/kernel/tasks.c
@@ -56,7 +56,9 @@ static readyqueues_t readyqueues[1] = {[0] = {task_table+0, NULL, 0, 0, 0, {[0 .
 
 DEFINE_PER_CORE(task_t*, current_task, task_table+0);
 DEFINE_PER_CORE(char*, kernel_stack, NULL);
+#if MAX_CORES > 1
 DEFINE_PER_CORE(uint32_t, __core_id, 0);
+#endif
 extern const void boot_stack;
 
 /** @brief helper function for the assembly code to determine the current task