diff --git a/soc/xtensa/esp32/esp32-mp.c b/soc/xtensa/esp32/esp32-mp.c
index ba194b1..db16667 100644
--- a/soc/xtensa/esp32/esp32-mp.c
+++ b/soc/xtensa/esp32/esp32-mp.c
@@ -273,7 +273,7 @@
 	}
 
 	cpus_active[0] = true;
-	cpus_active[CONFIG_MP_NUM_CPUS - 1] = true;
+	cpus_active[cpu_num] = true;
 
 	esp_intr_alloc(DT_IRQN(DT_NODELABEL(ipi0)),
 		ESP_INTR_FLAG_IRAM,