diff --git a/i386/Makefrag.am b/i386/Makefrag.am
index ea5149f..62ac61e 100644
--- a/i386/Makefrag.am
+++ b/i386/Makefrag.am
@@ -199,7 +199,7 @@ EXTRA_DIST += \
 	i386/ldscript
 if PLATFORM_at
 gnumach_LINKFLAGS += \
-	--defsym _START=0x100000 \
+	--defsym _START=0xC0100000 \
 	--defsym _START_MAP=0x100000 \
 	-T '$(srcdir)'/i386/ldscript
 endif
diff --git a/i386/i386/vm_param.h b/i386/i386/vm_param.h
index 4974c33..6abe412 100644
--- a/i386/i386/vm_param.h
+++ b/i386/i386/vm_param.h
@@ -34,7 +34,7 @@
 #define VM_MIN_KERNEL_ADDRESS	0xC0000000UL
 #define INIT_VM_MIN_KERNEL_ADDRESS	VM_MIN_KERNEL_ADDRESS
 #else	/* MACH_XEN */
-#define VM_MIN_KERNEL_ADDRESS	0x00000000UL
+#define VM_MIN_KERNEL_ADDRESS	0xC0000000UL
 #define INIT_VM_MIN_KERNEL_ADDRESS	0x00000000UL
 #endif	/* MACH_XEN */