diff --git a/components/esp_system/include/esp_private/startup_internal.h b/components/esp_system/include/esp_private/startup_internal.h
index 42b901cbf4..52ec6e09b3 100644
--- a/components/esp_system/include/esp_private/startup_internal.h
+++ b/components/esp_system/include/esp_private/startup_internal.h
@@ -31,10 +31,11 @@ extern bool g_spiram_ok; // [refactor-todo] better way to communicate this from
 // array, one per core.
 typedef void (*sys_startup_fn_t)(void);
 
+/* This array of per-CPU system layer startup functions is initialized in the non-port part of esp_system */
 #if !CONFIG_ESP_SYSTEM_SINGLE_CORE_MODE
-extern sys_startup_fn_t g_startup_fn[SOC_CPU_CORES_NUM];
+extern sys_startup_fn_t const g_startup_fn[SOC_CPU_CORES_NUM];
 #else
-extern sys_startup_fn_t g_startup_fn[1];
+extern sys_startup_fn_t const g_startup_fn[1];
 #endif
 
 // Utility to execute `sys_startup_fn_t` for the current core.
diff --git a/components/esp_system/startup.c b/components/esp_system/startup.c
index 4d398733dc..4acd8c34e6 100644
--- a/components/esp_system/startup.c
+++ b/components/esp_system/startup.c
@@ -113,7 +113,7 @@ void esp_startup_start_app_other_cores(void) __attribute__((weak, alias("esp_sta
 
 static volatile bool s_system_inited[SOC_CPU_CORES_NUM] = { false };
 
-sys_startup_fn_t g_startup_fn[SOC_CPU_CORES_NUM] = { [0] = start_cpu0,
+const sys_startup_fn_t g_startup_fn[SOC_CPU_CORES_NUM] = { [0] = start_cpu0,
 #if SOC_CPU_CORES_NUM > 1
     [1 ... SOC_CPU_CORES_NUM - 1] = start_cpu_other_cores
 #endif
@@ -121,7 +121,7 @@ sys_startup_fn_t g_startup_fn[SOC_CPU_CORES_NUM] = { [0] = start_cpu0,
 
 static volatile bool s_system_full_inited = false;
 #else
-sys_startup_fn_t g_startup_fn[1] = { start_cpu0 };
+const sys_startup_fn_t g_startup_fn[1] = { start_cpu0 };
 #endif
 
 #ifdef CONFIG_COMPILER_CXX_EXCEPTIONS