diff --git a/configs/pc99/autoconf.h b/configs/pc99/autoconf.h
index 92087499c..19b468f19 100644
--- a/configs/pc99/autoconf.h
+++ b/configs/pc99/autoconf.h
@@ -75,7 +75,7 @@
 #define CONFIG_HAVE_LIB_SEL4_SIMPLE 1
 #define CONFIG_HAVE_LIB_ELF 1
 #define CONFIG_HAVE_LIB_PLATSUPPORT 1
-#define CONFIG_NUM_DOMAINS 1
+#define CONFIG_NUM_DOMAINS 16
 #define CONFIG_ARCH_IA32 1
 #define CONFIG_HAVE_LIB_UTILS 1
 #define CONFIG_USER_OPTIMISATION_O2 1