diff --git a/components/esp_hw_support/include/esp_private/rtc_clk.h b/components/esp_hw_support/include/esp_private/rtc_clk.h
index 17c1a939b6..7edf69be06 100644
--- a/components/esp_hw_support/include/esp_private/rtc_clk.h
+++ b/components/esp_hw_support/include/esp_private/rtc_clk.h
@@ -44,12 +44,6 @@ void rtc_clk_bbpll_add_consumer(void);
  */
 void rtc_clk_bbpll_remove_consumer(void);
 
-/**
- * @brief Workaround for C2, S3, C6, H2. Trigger the calibration of PLL. Should be called when the bootloader doesn't provide a good enough PLL accuracy.
-*/
-void rtc_clk_recalib_bbpll(void);
-
-
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/esp_hw_support/port/esp32c2/rtc_clk.c b/components/esp_hw_support/port/esp32c2/rtc_clk.c
index 2501c2f6df..a494daba47 100644
--- a/components/esp_hw_support/port/esp32c2/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32c2/rtc_clk.c
@@ -358,24 +358,6 @@ bool rtc_dig_8m_enabled(void)
     return clk_ll_rc_fast_digi_is_enabled();
 }
 
-// Workaround for bootloader not calibrated well issue.
-// Placed in IRAM because disabling BBPLL may influence the cache
-void rtc_clk_recalib_bbpll(void)
-{
-    rtc_cpu_freq_config_t old_config;
-    rtc_clk_cpu_freq_get_config(&old_config);
-
-    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
-    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
-    //   Turn off the BBPLL and do calibration again to fix the issue.
-    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
-    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
-    if (old_config.source == SOC_CPU_CLK_SRC_PLL) {
-        rtc_clk_cpu_freq_set_xtal();
-        rtc_clk_cpu_freq_set_config(&old_config);
-    }
-}
-
 /* Name used in libphy.a:phy_chip_v7.o
  * TODO: update the library to use rtc_clk_xtal_freq_get
  */
diff --git a/components/esp_hw_support/port/esp32c6/rtc_clk.c b/components/esp_hw_support/port/esp32c6/rtc_clk.c
index 94256770bd..f7f30c2df7 100644
--- a/components/esp_hw_support/port/esp32c6/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32c6/rtc_clk.c
@@ -423,25 +423,6 @@ bool rtc_dig_8m_enabled(void)
     return clk_ll_rc_fast_digi_is_enabled();
 }
 
-// Workaround for bootloader not calibrated well issue.
-// Placed in IRAM because disabling BBPLL may influence the cache
-void rtc_clk_recalib_bbpll(void)
-{
-    rtc_cpu_freq_config_t old_config;
-    rtc_clk_cpu_freq_get_config(&old_config);
-
-    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
-    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
-    //   Turn off the BBPLL and do calibration again to fix the issue.
-    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
-    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
-    if (old_config.source == SOC_CPU_CLK_SRC_PLL) {
-        rtc_clk_cpu_freq_set_xtal();
-        rtc_clk_cpu_freq_set_config(&old_config);
-    }
-}
-
-
 /* Name used in libphy.a:phy_chip_v7.o
  * TODO: update the library to use rtc_clk_xtal_freq_get
  */
diff --git a/components/esp_hw_support/port/esp32h2/rtc_clk.c b/components/esp_hw_support/port/esp32h2/rtc_clk.c
index 1f6fd3b8fe..60db1c37a6 100644
--- a/components/esp_hw_support/port/esp32h2/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32h2/rtc_clk.c
@@ -239,7 +239,7 @@ static void rtc_clk_cpu_freq_to_pll_mhz(int cpu_freq_mhz)
 /**
  * Switch to FLASH_PLL as cpu clock source.
  * On ESP32H2, FLASH_PLL frequency is 64MHz.
- * PLL must alreay be enabled.
+ * PLL must already be enabled.
  */
 static void rtc_clk_cpu_freq_to_flash_pll(uint32_t cpu_freq_mhz, uint32_t cpu_divider)
 {
@@ -475,21 +475,3 @@ bool rtc_dig_8m_enabled(void)
 {
     return clk_ll_rc_fast_digi_is_enabled();
 }
-
-// Workaround for bootloader not calibrated well issue.
-// Placed in IRAM because disabling BBPLL may influence the cache
-void rtc_clk_recalib_bbpll(void)
-{
-    rtc_cpu_freq_config_t old_config;
-    rtc_clk_cpu_freq_get_config(&old_config);
-
-    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
-    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
-    //   Turn off the BBPLL and do calibration again to fix the issue. Flash_PLL comes from the same source as PLL.
-    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
-    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
-    if (old_config.source == SOC_CPU_CLK_SRC_PLL || old_config.source == SOC_CPU_CLK_SRC_FLASH_PLL) {
-        rtc_clk_cpu_freq_set_xtal();
-        rtc_clk_cpu_freq_set_config(&old_config);
-    }
-}
diff --git a/components/esp_hw_support/port/esp32s3/rtc_clk.c b/components/esp_hw_support/port/esp32s3/rtc_clk.c
index ae059e1233..2017637f82 100644
--- a/components/esp_hw_support/port/esp32s3/rtc_clk.c
+++ b/components/esp_hw_support/port/esp32s3/rtc_clk.c
@@ -189,7 +189,7 @@ static void rtc_clk_bbpll_configure(rtc_xtal_freq_t xtal_freq, int pll_freq)
  */
 static void rtc_clk_cpu_freq_to_pll_mhz(int cpu_freq_mhz)
 {
-    /* There are totally 6 LDO slaves(all on by default). At the moment of swithing LDO slave, LDO voltage will also change instantaneously.
+    /* There are totally 6 LDO slaves(all on by default). At the moment of switching LDO slave, LDO voltage will also change instantaneously.
      * LDO slave can reduce the voltage change caused by switching frequency.
      * CPU frequency <= 40M : just open 3 LDO slaves; CPU frequency = 80M : open 4 LDO slaves; CPU frequency = 160M : open 5 LDO slaves; CPU frequency = 240M : open 6 LDO slaves;
      *
@@ -463,25 +463,6 @@ bool rtc_dig_8m_enabled(void)
     return clk_ll_rc_fast_digi_is_enabled();
 }
 
-// Workaround for bootloader not calibrated well issue.
-// Placed in IRAM because disabling BBPLL may influence the cache
-void rtc_clk_recalib_bbpll(void)
-{
-    rtc_cpu_freq_config_t old_config;
-    rtc_clk_cpu_freq_get_config(&old_config);
-
-    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
-    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
-    //   Turn off the BBPLL and do calibration again to fix the issue.
-    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
-    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
-    if (old_config.source == SOC_CPU_CLK_SRC_PLL) {
-        rtc_clk_cpu_freq_set_xtal();
-        rtc_clk_cpu_freq_set_config(&old_config);
-    }
-}
-
-
 /* Name used in libphy.a:phy_chip_v7.o
  * TODO: update the library to use rtc_clk_xtal_freq_get
  */
diff --git a/components/esp_system/fpga_overrides.c b/components/esp_system/fpga_overrides.c
index 24e5e2f909..9e448019e9 100644
--- a/components/esp_system/fpga_overrides.c
+++ b/components/esp_system/fpga_overrides.c
@@ -64,14 +64,18 @@ void IRAM_ATTR bootloader_fill_random(void *buffer, size_t length)
     }
 }
 
-void esp_clk_init(void)
+void esp_rtc_init(void)
 {
-    s_warn();
 #if SOC_PMU_SUPPORTED
     pmu_init();
 #endif
 }
 
+void esp_clk_init(void)
+{
+    s_warn();
+}
+
 void esp_perip_clk_init(void)
 {
 
diff --git a/components/esp_system/port/cpu_start.c b/components/esp_system/port/cpu_start.c
index 1322648c74..6e234b43a1 100644
--- a/components/esp_system/port/cpu_start.c
+++ b/components/esp_system/port/cpu_start.c
@@ -457,6 +457,10 @@ void IRAM_ATTR call_start_cpu0(void)
     // For Octal flash, it's hard to implement a read_id function in OPI mode for all vendors.
     // So we have to read it here in SPI mode, before entering the OPI mode.
     bootloader_flash_update_id();
+
+    // Configure the power related stuff. After this the MSPI timing tuning can be done.
+    esp_rtc_init();
+
     /**
      * This function initialise the Flash chip to the user-defined settings.
      *
@@ -465,14 +469,9 @@ void IRAM_ATTR call_start_cpu0(void)
      * In this stage, we re-configure the Flash (and MSPI) to required configuration
      */
     spi_flash_init_chip_state();
-
-    // In earlier version of ESP-IDF, the PLL provided by bootloader is not stable enough.
-    // Do calibration again here so that we can use better clock for the timing tuning.
-#if CONFIG_ESP_SYSTEM_BBPLL_RECALIB
-    rtc_clk_recalib_bbpll();
-#endif
 #if SOC_MEMSPI_SRC_FREQ_120M
-    // This function needs to be called when PLL is enabled
+    // This function needs to be called when PLL is enabled. Needs to be called after spi_flash_init_chip_state in case
+    // some state of flash is modified.
     mspi_timing_flash_tuning();
 #endif
 
diff --git a/components/esp_system/port/include/esp_clk_internal.h b/components/esp_system/port/include/esp_clk_internal.h
index b69d7cfcea..72b6b20b92 100644
--- a/components/esp_system/port/include/esp_clk_internal.h
+++ b/components/esp_system/port/include/esp_clk_internal.h
@@ -18,6 +18,15 @@ extern "C" {
  * Private clock-related functions
  */
 
+/**
+ * @brief Initialize rtc-related settings
+ *
+ * Called from cpu_start.c, not intended to be called from other places.
+ * This function configures the power related stuff.
+ * After this the MSPI timing tuning can be done.
+ */
+void esp_rtc_init(void);
+
 /**
  * @brief Initialize clock-related settings
  *
diff --git a/components/esp_system/port/soc/esp32/clk.c b/components/esp_system/port/soc/esp32/clk.c
index 5ec87cca7f..f8f1edf332 100644
--- a/components/esp_system/port/soc/esp32/clk.c
+++ b/components/esp_system/port/soc/esp32/clk.c
@@ -106,11 +106,14 @@ static void select_rtc_slow_clk(slow_clk_sel_t slow_clk)
     esp_clk_slowclk_cal_set(cal_val);
 }
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
     rtc_config_t cfg = RTC_CONFIG_DEFAULT();
     rtc_init(cfg);
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
 #if (CONFIG_APP_COMPATIBLE_PRE_V2_1_BOOTLOADERS || CONFIG_APP_INIT_CLK)
     /* Check the bootloader set the XTAL frequency.
 
diff --git a/components/esp_system/port/soc/esp32c2/clk.c b/components/esp_system/port/soc/esp32c2/clk.c
index 92e7e1bb39..3d52e3ab56 100644
--- a/components/esp_system/port/soc/esp32c2/clk.c
+++ b/components/esp_system/port/soc/esp32c2/clk.c
@@ -51,12 +51,19 @@ typedef enum {
 } slow_clk_sel_t;
 
 static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
+static __attribute__((unused)) void recalib_bbpll(void);
 
 static const char *TAG = "clk";
 
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
+#if CONFIG_ESP_SYSTEM_BBPLL_RECALIB
+    // In earlier version of ESP-IDF, the PLL provided by bootloader is not stable enough.
+    // Do calibration again here so that we can use better clock for the timing tuning.
+    recalib_bbpll();
+#endif
+
 #if !CONFIG_IDF_ENV_FPGA
     rtc_config_t cfg = RTC_CONFIG_DEFAULT();
     soc_reset_reason_t rst_reas;
@@ -65,7 +72,12 @@ static const char *TAG = "clk";
         cfg.cali_ocode = 1;
     }
     rtc_init(cfg);
+#endif
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
+#if !CONFIG_IDF_ENV_FPGA
 #ifndef CONFIG_XTAL_FREQ_AUTO
     assert(rtc_clk_xtal_freq_get() == CONFIG_XTAL_FREQ);
 #endif
@@ -266,3 +278,21 @@ __attribute__((weak)) void esp_perip_clk_init(void)
      */
     periph_module_enable(PERIPH_TIMG0_MODULE);
 }
+
+// Workaround for bootloader not calibrated well issue.
+// Placed in IRAM because disabling BBPLL may influence the cache
+static void IRAM_ATTR NOINLINE_ATTR recalib_bbpll(void)
+{
+    rtc_cpu_freq_config_t old_config;
+    rtc_clk_cpu_freq_get_config(&old_config);
+
+    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
+    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
+    //   Turn off the BBPLL and do calibration again to fix the issue.
+    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
+    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
+    if (old_config.source == SOC_CPU_CLK_SRC_PLL) {
+        rtc_clk_cpu_freq_set_xtal();
+        rtc_clk_cpu_freq_set_config(&old_config);
+    }
+}
diff --git a/components/esp_system/port/soc/esp32c3/clk.c b/components/esp_system/port/soc/esp32c3/clk.c
index b92318053d..65889101b4 100644
--- a/components/esp_system/port/soc/esp32c3/clk.c
+++ b/components/esp_system/port/soc/esp32c3/clk.c
@@ -56,7 +56,7 @@ static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
 static const char *TAG = "clk";
 
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
 #if !CONFIG_IDF_ENV_FPGA
     rtc_config_t cfg = RTC_CONFIG_DEFAULT();
@@ -70,7 +70,10 @@ static const char *TAG = "clk";
         cfg.cali_ocode = 1;
     }
     rtc_init(cfg);
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
     assert(rtc_clk_xtal_freq_get() == RTC_XTAL_FREQ_40M);
 
     bool rc_fast_d256_is_enabled = rtc_clk_8md256_enabled();
diff --git a/components/esp_system/port/soc/esp32c6/clk.c b/components/esp_system/port/soc/esp32c6/clk.c
index 92487e6637..606ec40d61 100644
--- a/components/esp_system/port/soc/esp32c6/clk.c
+++ b/components/esp_system/port/soc/esp32c6/clk.c
@@ -37,18 +37,30 @@
 #define MHZ (1000000)
 
 static void select_rtc_slow_clk(soc_rtc_slow_clk_src_t rtc_slow_clk_src);
+static __attribute__((unused)) void recalib_bbpll(void);
 
 static const char *TAG = "clk";
 
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
+#if CONFIG_ESP_SYSTEM_BBPLL_RECALIB
+    // In earlier version of ESP-IDF, the PLL provided by bootloader is not stable enough.
+    // Do calibration again here so that we can use better clock for the timing tuning.
+    recalib_bbpll();
+#endif
+
 #if !CONFIG_IDF_ENV_FPGA
     pmu_init();
     if (esp_rom_get_reset_reason(0) == RESET_REASON_CHIP_POWER_ON) {
         esp_ocode_calib_init();
     }
+#endif
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
+#if !CONFIG_IDF_ENV_FPGA
     assert(rtc_clk_xtal_freq_get() == RTC_XTAL_FREQ_40M);
 
     rtc_clk_8m_enable(true);
@@ -302,3 +314,21 @@ __attribute__((weak)) void esp_perip_clk_init(void)
      */
     periph_module_enable(PERIPH_TIMG0_MODULE);
 }
+
+// Workaround for bootloader not calibrated well issue.
+// Placed in IRAM because disabling BBPLL may influence the cache
+static void IRAM_ATTR NOINLINE_ATTR recalib_bbpll(void)
+{
+    rtc_cpu_freq_config_t old_config;
+    rtc_clk_cpu_freq_get_config(&old_config);
+
+    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
+    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
+    //   Turn off the BBPLL and do calibration again to fix the issue.
+    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
+    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
+    if (old_config.source == SOC_CPU_CLK_SRC_PLL) {
+        rtc_clk_cpu_freq_set_xtal();
+        rtc_clk_cpu_freq_set_config(&old_config);
+    }
+}
diff --git a/components/esp_system/port/soc/esp32h2/clk.c b/components/esp_system/port/soc/esp32h2/clk.c
index 8ced39f8e4..39a781b648 100644
--- a/components/esp_system/port/soc/esp32h2/clk.c
+++ b/components/esp_system/port/soc/esp32h2/clk.c
@@ -37,15 +37,27 @@
 #define MHZ (1000000)
 
 static void select_rtc_slow_clk(soc_rtc_slow_clk_src_t rtc_slow_clk_src);
+static __attribute__((unused)) void recalib_bbpll(void);
 
 static const char *TAG = "clk";
 
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
+#if CONFIG_ESP_SYSTEM_BBPLL_RECALIB
+    // In earlier version of ESP-IDF, the PLL provided by bootloader is not stable enough.
+    // Do calibration again here so that we can use better clock for the timing tuning.
+    recalib_bbpll();
+#endif
+
 #if !CONFIG_IDF_ENV_FPGA
     pmu_init();
+#endif
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
+#if !CONFIG_IDF_ENV_FPGA
     assert(rtc_clk_xtal_freq_get() == RTC_XTAL_FREQ_32M);
 
     rtc_clk_8m_enable(true);
@@ -296,3 +308,21 @@ __attribute__((weak)) void esp_perip_clk_init(void)
      */
     periph_module_enable(PERIPH_TIMG0_MODULE);
 }
+
+// Workaround for bootloader not calibrated well issue.
+// Placed in IRAM because disabling BBPLL may influence the cache
+static void IRAM_ATTR NOINLINE_ATTR recalib_bbpll(void)
+{
+    rtc_cpu_freq_config_t old_config;
+    rtc_clk_cpu_freq_get_config(&old_config);
+
+    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
+    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
+    //   Turn off the BBPLL and do calibration again to fix the issue. Flash_PLL comes from the same source as PLL.
+    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
+    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
+    if (old_config.source == SOC_CPU_CLK_SRC_PLL || old_config.source == SOC_CPU_CLK_SRC_FLASH_PLL) {
+        rtc_clk_cpu_freq_set_xtal();
+        rtc_clk_cpu_freq_set_config(&old_config);
+    }
+}
diff --git a/components/esp_system/port/soc/esp32s2/clk.c b/components/esp_system/port/soc/esp32s2/clk.c
index 2f82f73161..7e3d2ab239 100644
--- a/components/esp_system/port/soc/esp32s2/clk.c
+++ b/components/esp_system/port/soc/esp32s2/clk.c
@@ -60,7 +60,7 @@ typedef enum {
 
 static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
     rtc_config_t cfg = RTC_CONFIG_DEFAULT();
     soc_reset_reason_t rst_reas = esp_rom_get_reset_reason(0);
@@ -74,7 +74,10 @@ static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
         }
     }
     rtc_init(cfg);
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
     bool rc_fast_d256_is_enabled = rtc_clk_8md256_enabled();
     rtc_clk_8m_enable(true, rc_fast_d256_is_enabled);
     rtc_clk_fast_src_set(SOC_RTC_FAST_CLK_SRC_RC_FAST);
diff --git a/components/esp_system/port/soc/esp32s3/clk.c b/components/esp_system/port/soc/esp32s3/clk.c
index 2f44c62bcf..19f8b7dff0 100644
--- a/components/esp_system/port/soc/esp32s3/clk.c
+++ b/components/esp_system/port/soc/esp32s3/clk.c
@@ -53,9 +53,16 @@ typedef enum {
 } slow_clk_sel_t;
 
 static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
+static __attribute__((unused)) void recalib_bbpll(void);
 
- __attribute__((weak)) void esp_clk_init(void)
+void esp_rtc_init(void)
 {
+#if CONFIG_ESP_SYSTEM_BBPLL_RECALIB
+    // In earlier version of ESP-IDF, the PLL provided by bootloader is not stable enough.
+    // Do calibration again here so that we can use better clock for the timing tuning.
+    recalib_bbpll();
+#endif
+
     rtc_config_t cfg = RTC_CONFIG_DEFAULT();
     soc_reset_reason_t rst_reas;
     rst_reas = esp_rom_get_reset_reason(0);
@@ -64,7 +71,10 @@ static void select_rtc_slow_clk(slow_clk_sel_t slow_clk);
         cfg.cali_ocode = 1;
     }
     rtc_init(cfg);
+}
 
+__attribute__((weak)) void esp_clk_init(void)
+{
     assert(rtc_clk_xtal_freq_get() == RTC_XTAL_FREQ_40M);
 
     bool rc_fast_d256_is_enabled = rtc_clk_8md256_enabled();
@@ -324,3 +334,21 @@ __attribute__((weak)) void esp_perip_clk_init(void)
      */
     periph_module_enable(PERIPH_TIMG0_MODULE);
 }
+
+// Workaround for bootloader not calibrated well issue.
+// Placed in IRAM because disabling BBPLL may influence the cache
+static void IRAM_ATTR NOINLINE_ATTR recalib_bbpll(void)
+{
+    rtc_cpu_freq_config_t old_config;
+    rtc_clk_cpu_freq_get_config(&old_config);
+
+    // There are two paths we arrive here: 1. CPU reset. 2. Other reset reasons.
+    // - For other reasons, the bootloader will set CPU source to BBPLL and enable it. But there are calibration issues.
+    //   Turn off the BBPLL and do calibration again to fix the issue.
+    // - For CPU reset, the CPU source will be set to XTAL, while the BBPLL is kept to meet USB Serial JTAG's
+    //   requirements. In this case, we don't touch BBPLL to avoid USJ disconnection.
+    if (old_config.source == SOC_CPU_CLK_SRC_PLL) {
+        rtc_clk_cpu_freq_set_xtal();
+        rtc_clk_cpu_freq_set_config(&old_config);
+    }
+}