diff --git a/components/bt/host/bluedroid/api/esp_gap_ble_api.c b/components/bt/host/bluedroid/api/esp_gap_ble_api.c
index 067de4d9871..311c5d281ca 100644
--- a/components/bt/host/bluedroid/api/esp_gap_ble_api.c
+++ b/components/bt/host/bluedroid/api/esp_gap_ble_api.c
@@ -154,8 +154,8 @@ esp_err_t esp_ble_gap_update_conn_params(esp_ble_conn_update_params_t *params)
         return ESP_FAIL;
     }
 
-    if (ESP_BLE_IS_VALID_PARAM(params->min_int, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-        ESP_BLE_IS_VALID_PARAM(params->max_int, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+    if (ESP_BLE_IS_VALID_PARAM(params->min_int, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+        ESP_BLE_IS_VALID_PARAM(params->max_int, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
         ESP_BLE_IS_VALID_PARAM(params->timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
         (params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
         ((params->timeout * 10) >= ((1 + params->latency) * ((params->max_int * 5) >> 1))) && params->min_int <= params->max_int) {
@@ -393,8 +393,8 @@ esp_err_t esp_ble_gap_set_prefer_conn_params(esp_bd_addr_t bd_addr,
         return ESP_ERR_INVALID_ARG;
     }
 
-    if (ESP_BLE_IS_VALID_PARAM(min_conn_int, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-        ESP_BLE_IS_VALID_PARAM(max_conn_int, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+    if (ESP_BLE_IS_VALID_PARAM(min_conn_int, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+        ESP_BLE_IS_VALID_PARAM(max_conn_int, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
         ESP_BLE_IS_VALID_PARAM(supervision_tout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
         (slave_latency <= ESP_BLE_CONN_LATENCY_MAX) &&
         ((supervision_tout * 10) >= ((1 + slave_latency) * ((max_conn_int * 5) >> 1))) && min_conn_int <= max_conn_int) {
@@ -1747,8 +1747,8 @@ esp_err_t esp_ble_gap_prefer_ext_connect_params_set(esp_bd_addr_t addr,
             return ESP_ERR_INVALID_ARG;
         }
 
-        if (ESP_BLE_IS_VALID_PARAM(phy_1m_conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(phy_1m_conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(phy_1m_conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(phy_1m_conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(phy_1m_conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (phy_1m_conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((phy_1m_conn_params->supervision_timeout * 10) >= ((1 + phy_1m_conn_params->latency) * ((phy_1m_conn_params->interval_max * 5) >> 1))) &&
@@ -1771,8 +1771,8 @@ esp_err_t esp_ble_gap_prefer_ext_connect_params_set(esp_bd_addr_t addr,
             return ESP_ERR_INVALID_ARG;
         }
 
-        if (ESP_BLE_IS_VALID_PARAM(phy_2m_conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(phy_2m_conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(phy_2m_conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(phy_2m_conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(phy_2m_conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (phy_2m_conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((phy_2m_conn_params->supervision_timeout * 10) >= ((1 + phy_2m_conn_params->latency) * ((phy_2m_conn_params->interval_max * 5) >> 1))) &&
@@ -1795,8 +1795,8 @@ esp_err_t esp_ble_gap_prefer_ext_connect_params_set(esp_bd_addr_t addr,
             return ESP_ERR_INVALID_ARG;
         }
 
-        if (ESP_BLE_IS_VALID_PARAM(phy_coded_conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(phy_coded_conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(phy_coded_conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(phy_coded_conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(phy_coded_conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (phy_coded_conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((phy_coded_conn_params->supervision_timeout * 10) >= ((1 + phy_coded_conn_params->latency) * ((phy_coded_conn_params->interval_max * 5) >> 1))) &&
diff --git a/components/bt/host/bluedroid/api/esp_gattc_api.c b/components/bt/host/bluedroid/api/esp_gattc_api.c
index b0d2458ca3c..0e2befd18d7 100644
--- a/components/bt/host/bluedroid/api/esp_gattc_api.c
+++ b/components/bt/host/bluedroid/api/esp_gattc_api.c
@@ -115,8 +115,8 @@ esp_err_t esp_ble_gattc_enh_open(esp_gatt_if_t gattc_if, esp_ble_gatt_creat_conn
         }
 
         conn_params = creat_conn_params->phy_1m_conn_params;
-        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((conn_params->supervision_timeout * 10) >= ((1 + conn_params->latency) * ((conn_params->interval_max * 5) >> 1))) &&
@@ -138,8 +138,8 @@ esp_err_t esp_ble_gattc_enh_open(esp_gatt_if_t gattc_if, esp_ble_gatt_creat_conn
         }
 
         conn_params = creat_conn_params->phy_2m_conn_params;
-        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((conn_params->supervision_timeout * 10) >= ((1 + conn_params->latency) * ((conn_params->interval_max * 5) >> 1))) &&
@@ -161,8 +161,8 @@ esp_err_t esp_ble_gattc_enh_open(esp_gatt_if_t gattc_if, esp_ble_gatt_creat_conn
         }
 
         conn_params = creat_conn_params->phy_coded_conn_params;
-        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((conn_params->supervision_timeout * 10) >= ((1 + conn_params->latency) * ((conn_params->interval_max * 5) >> 1))) &&
@@ -251,8 +251,8 @@ esp_err_t esp_ble_gattc_aux_open_with_pawr_synced(esp_gatt_if_t gattc_if, esp_bl
         }
 
         conn_params = pawr_conn_params->phy_1m_conn_params;
-        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((conn_params->supervision_timeout * 10) >= ((1 + conn_params->latency) * ((conn_params->interval_max * 5) >> 1))) &&
@@ -274,8 +274,8 @@ esp_err_t esp_ble_gattc_aux_open_with_pawr_synced(esp_gatt_if_t gattc_if, esp_bl
         }
 
         conn_params = pawr_conn_params->phy_2m_conn_params;
-        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((conn_params->supervision_timeout * 10) >= ((1 + conn_params->latency) * ((conn_params->interval_max * 5) >> 1))) &&
@@ -297,8 +297,8 @@ esp_err_t esp_ble_gattc_aux_open_with_pawr_synced(esp_gatt_if_t gattc_if, esp_bl
         }
 
         conn_params = pawr_conn_params->phy_coded_conn_params;
-        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
-            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, ESP_BLE_CONN_INT_MIN, ESP_BLE_CONN_INT_MAX) &&
+        if (ESP_BLE_IS_VALID_PARAM(conn_params->interval_min, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
+            ESP_BLE_IS_VALID_PARAM(conn_params->interval_max, BLE_CONN_INT_MIN_HOST_CHECK, ESP_BLE_CONN_INT_MAX) &&
             ESP_BLE_IS_VALID_PARAM(conn_params->supervision_timeout, ESP_BLE_CONN_SUP_TOUT_MIN, ESP_BLE_CONN_SUP_TOUT_MAX) &&
             (conn_params->latency <= ESP_BLE_CONN_LATENCY_MAX) &&
             ((conn_params->supervision_timeout * 10) >= ((1 + conn_params->latency) * ((conn_params->interval_max * 5) >> 1))) &&
diff --git a/components/bt/host/bluedroid/api/include/api/esp_bt_defs.h b/components/bt/host/bluedroid/api/include/api/esp_bt_defs.h
index e4c9b9719db..bd4b2c7e763 100644
--- a/components/bt/host/bluedroid/api/include/api/esp_bt_defs.h
+++ b/components/bt/host/bluedroid/api/include/api/esp_bt_defs.h
@@ -216,12 +216,11 @@ typedef uint8_t esp_link_key[ESP_BT_OCTET16_LEN];      /* Link Key */
 #define ESP_BLE_PRIM_ADV_INT_MIN            0x000020     /*!< Minimum advertising interval for undirected and low duty cycle directed advertising */
 #endif
 #define ESP_BLE_PRIM_ADV_INT_MAX            0xFFFFFF     /*!< Maximum advertising interval for undirected and low duty cycle directed advertising */
-/* Lower bound (1.25 ms units) for host-side connection interval checks.*/
-#if defined(CONFIG_BT_BLE_HOST_ALLOW_SUB_SPEC_MIN_CONN_INT) && (CONFIG_BT_BLE_HOST_ALLOW_SUB_SPEC_MIN_CONN_INT)
-#define ESP_BLE_CONN_INT_MIN                0x0001
-#else
-#define ESP_BLE_CONN_INT_MIN                0x0006
-#endif
+/* Public API constant pinned to the Bluetooth Core Spec minimum (7.5 ms).
+ * Applications that want a sub-spec connection interval must pass the
+ * desired value as an integer literal; whether it is actually accepted
+ * depends on the controller. */
+#define ESP_BLE_CONN_INT_MIN                0x0006       /*!< Minimum connection interval, 7.5 ms (BLE Core Spec minimum) */
 #define ESP_BLE_CONN_INT_MAX                0x0C80       /*!< relate to BTM_BLE_CONN_INT_MAX in stack/btm_ble_api.h */
 #define ESP_BLE_CONN_LATENCY_MAX            499          /*!< relate to ESP_BLE_CONN_LATENCY_MAX in stack/btm_ble_api.h */
 #define ESP_BLE_CONN_SUP_TOUT_MIN           0x000A       /*!< relate to BTM_BLE_CONN_SUP_TOUT_MIN in stack/btm_ble_api.h */
@@ -238,8 +237,8 @@ typedef uint8_t esp_ble_phy_mask_t;
 typedef struct {
     uint16_t scan_interval;       /*!< Initial scan interval, in units of 0.625ms, the range is 0x0004(2.5ms) to 0xFFFF(10.24s). */
     uint16_t scan_window;         /*!< Initial scan window, in units of 0.625ms, the range is 0x0004(2.5ms) to 0xFFFF(10.24s). */
-    uint16_t interval_min;        /*!< Minimum connection interval, in units of 1.25 ms. Host validation uses ESP_BLE_CONN_INT_MIN as the lower bound; the interval the controller ultimately allows may be higher depending on its capability. Upper bound 0x0C80 (4 s). */
-    uint16_t interval_max;        /*!< Maximum connection interval, in units of 1.25 ms. Same bounds as interval_min. */
+    uint16_t interval_min;        /*!< Minimum connection interval, in units of 1.25 ms, the range is 0x0006(7.5ms) to 0x0C80(4s). Sub-spec values are accepted only if the controller supports them. */
+    uint16_t interval_max;        /*!< Maximum connection interval, in units of 1.25 ms, the range is 0x0006(7.5ms) to 0x0C80(4s). Same bounds as interval_min. */
     uint16_t latency;             /*!< Connection latency, the range is 0x0000(0) to 0x01F3(499). */
     uint16_t supervision_timeout; /*!< Connection supervision timeout, in units of 10ms, the range is from 0x000A(100ms) to 0x0C80(32s). */
     uint16_t min_ce_len;          /*!< Minimum connection event length, in units of 0.625ms, setting to 0 for no preferred parameters. */
diff --git a/components/bt/host/bluedroid/btc/profile/std/gap/btc_gap_ble.c b/components/bt/host/bluedroid/btc/profile/std/gap/btc_gap_ble.c
index 76ce330e529..b886849626b 100644
--- a/components/bt/host/bluedroid/btc/profile/std/gap/btc_gap_ble.c
+++ b/components/bt/host/bluedroid/btc/profile/std/gap/btc_gap_ble.c
@@ -1958,7 +1958,7 @@ static void btc_ble_update_conn_params(BD_ADDR bd_addr, uint16_t min_int,
         min_int = max_int;
     }
 
-    if (min_int < BTM_BLE_CONN_INT_MIN || max_int > BTM_BLE_CONN_INT_MAX) {
+    if (min_int < BLE_CONN_INT_MIN_HOST_CHECK || max_int > BTM_BLE_CONN_INT_MAX) {
         BTC_TRACE_ERROR("Invalid interval value.\n");
     }
 
diff --git a/components/bt/host/bluedroid/common/include/common/bluedroid_user_config.h b/components/bt/host/bluedroid/common/include/common/bluedroid_user_config.h
index 07bd62f1684..7caa9e6261a 100644
--- a/components/bt/host/bluedroid/common/include/common/bluedroid_user_config.h
+++ b/components/bt/host/bluedroid/common/include/common/bluedroid_user_config.h
@@ -382,19 +382,12 @@
 #define UC_BT_BLE_HIGH_DUTY_ADV_INTERVAL FALSE
 #endif
 
-/* Controls whether the Bluedroid host enforces the Bluetooth Core
- * specification minimum BLE connection interval (0x0006 / 7.5 ms) during
- * host-side parameter validation.
- *
- *   - 1 : host-side lower bound is relaxed to 0x0001 (1.25 ms). The real
- *         lower bound is then enforced solely by the BLE controller.
- *   - 0 : host enforces the Bluetooth Core spec minimum (0x0006).
+/* When set to 1, the Bluedroid host's parameter validation no longer enforces
+ * a minimum BLE connection interval; the actual lower limit is then left to
+ * the controller. See BLE_CONN_INT_MIN_HOST_CHECK in common/bt_target.h.
  *
  * Do not turn this on manually in menuconfig unless you know the implications.
- * In normal IDF builds it follows the active Controller integration. The
- * actual minimum connection interval is defined by the Controller, not by the
- * Host; Controller configuration option names differ by chip and stack.
- * See common/bt_target.h (BLE_CONN_INT_MIN_HW). */
+ * In normal IDF builds it follows the active Controller integration. */
 #ifdef CONFIG_BT_BLE_HOST_ALLOW_SUB_SPEC_MIN_CONN_INT
 #define UC_BT_BLE_HOST_ALLOW_SUB_SPEC_MIN_CONN_INT      1
 #else
diff --git a/components/bt/host/bluedroid/common/include/common/bt_target.h b/components/bt/host/bluedroid/common/include/common/bt_target.h
index 76f4a14ab06..99d6254d092 100644
--- a/components/bt/host/bluedroid/common/include/common/bt_target.h
+++ b/components/bt/host/bluedroid/common/include/common/bt_target.h
@@ -437,28 +437,21 @@
 #define BLE_HIGH_DUTY_ADV_INTERVAL FALSE
 #endif
 
-/* Minimum BLE connection interval (in 1.25 ms units) enforced by the Bluedroid
- * host parameter validation.
+/* Host-side parameter validation floor (in 1.25 ms units) for the BLE
+ * connection interval. Internal to the Bluedroid host: not sent on air, not
+ * exposed via the GATT Preferred Connection Parameters Characteristic, and
+ * not a public API constant - those use BTM_BLE_CONN_INT_MIN (0x0006).
  *
- *   - When host-side validation keeps the Core Spec floor: 0x0006 (7.5 ms).
- *   - When validation is relaxed for sub-spec intervals: 0x0001 (1.25 ms) so
- *     host-side checks no longer enforce the Core Spec minimum; whether a
- *     smaller connection interval is allowed and the real lower limit depend
- *     entirely on Controller capability and its own configuration (option
- *     names differ by Controller). Whether the relaxed mode is used is
- *     determined by how the Host is integrated with the Controller for each
- *     product, not documented here.
- *
- * Note: the relaxed lower bound is 0x0001 rather than 0x0000 so that all
- * existing `uint16_t < MIN` / `uint16_t >= MIN` range checks in the stack
- * remain well-defined under GCC `-Wtype-limits`. Since 0 is not a valid HCI
- * connection interval anyway, this is functionally equivalent to disabling
- * the host-side minimum check. */
-#ifndef BLE_CONN_INT_MIN_HW
+ * When UC_BT_BLE_HOST_ALLOW_SUB_SPEC_MIN_CONN_INT == 1 the host stops
+ * enforcing a minimum (the actual lower limit is then defined entirely by
+ * the controller). 0x0001 is used rather than 0x0000 so the existing
+ * `uint16_t < MIN` range checks remain well-defined under GCC
+ * `-Wtype-limits`. */
+#ifndef BLE_CONN_INT_MIN_HOST_CHECK
 #if (UC_BT_BLE_HOST_ALLOW_SUB_SPEC_MIN_CONN_INT == 1)
-#define BLE_CONN_INT_MIN_HW             0x0001
+#define BLE_CONN_INT_MIN_HOST_CHECK             0x0001
 #else
-#define BLE_CONN_INT_MIN_HW             0x0006
+#define BLE_CONN_INT_MIN_HOST_CHECK             0x0006
 #endif
 #endif
 
diff --git a/components/bt/host/bluedroid/stack/btm/btm_ble.c b/components/bt/host/bluedroid/stack/btm/btm_ble.c
index 71dcdc0768b..95b44c35889 100644
--- a/components/bt/host/bluedroid/stack/btm/btm_ble.c
+++ b/components/bt/host/bluedroid/stack/btm/btm_ble.c
@@ -578,8 +578,8 @@ void BTM_BleSetPrefConnParams (BD_ADDR bd_addr,
                     tout: %u",
                    min_conn_int, max_conn_int, slave_latency, supervision_tout);
 
-    if (BTM_BLE_ISVALID_PARAM(min_conn_int, BTM_BLE_CONN_INT_MIN, BTM_BLE_CONN_INT_MAX) &&
-            BTM_BLE_ISVALID_PARAM(max_conn_int, BTM_BLE_CONN_INT_MIN, BTM_BLE_CONN_INT_MAX) &&
+    if (BTM_BLE_ISVALID_PARAM(min_conn_int, BLE_CONN_INT_MIN_HOST_CHECK, BTM_BLE_CONN_INT_MAX) &&
+            BTM_BLE_ISVALID_PARAM(max_conn_int, BLE_CONN_INT_MIN_HOST_CHECK, BTM_BLE_CONN_INT_MAX) &&
             BTM_BLE_ISVALID_PARAM(supervision_tout, BTM_BLE_CONN_SUP_TOUT_MIN, BTM_BLE_CONN_SUP_TOUT_MAX) &&
             (slave_latency <= BTM_BLE_CONN_LATENCY_MAX || slave_latency == BTM_BLE_CONN_PARAM_UNDEF)) {
         if (p_dev_rec) {
diff --git a/components/bt/host/bluedroid/stack/include/stack/btm_ble_api.h b/components/bt/host/bluedroid/stack/include/stack/btm_ble_api.h
index 27fdf5f5b2a..6084ffa6afa 100644
--- a/components/bt/host/bluedroid/stack/include/stack/btm_ble_api.h
+++ b/components/bt/host/bluedroid/stack/include/stack/btm_ble_api.h
@@ -122,7 +122,12 @@ typedef UINT8   tBTM_BLE_SFP;
 #define BTM_BLE_SCAN_INT_MAX            0x4000
 #define BTM_BLE_SCAN_WIN_MIN            0x0004
 #define BTM_BLE_SCAN_WIN_MAX            0x4000
-#define BTM_BLE_CONN_INT_MIN            BLE_CONN_INT_MIN_HW   /* host-side check limit; see BLE_CONN_INT_MIN_HW in common/bt_target.h */
+/* Bluetooth Core Spec minimum BLE connection interval (7.5 ms). Used inside
+ * the host stack wherever the on-air or interoperability semantics require
+ * the spec value. For host-side parameter validation (which can be relaxed
+ * to accept sub-spec intervals) use BLE_CONN_INT_MIN_HOST_CHECK from
+ * common/bt_target.h instead. */
+#define BTM_BLE_CONN_INT_MIN            0x0006
 #define BTM_BLE_CONN_INT_MAX            0x0C80
 #define BTM_BLE_CONN_LATENCY_MAX        499
 #define BTM_BLE_CONN_SUP_TOUT_MIN       0x000A
diff --git a/components/bt/host/bluedroid/stack/l2cap/l2c_ble.c b/components/bt/host/bluedroid/stack/l2cap/l2c_ble.c
index 817d0b94b83..65d4e643b06 100644
--- a/components/bt/host/bluedroid/stack/l2cap/l2c_ble.c
+++ b/components/bt/host/bluedroid/stack/l2cap/l2c_ble.c
@@ -377,9 +377,9 @@ void l2cble_scanner_conn_comp (UINT16 handle, BD_ADDR bda, tBLE_ADDR_TYPE type,
     p_lcb->ble_addr_type = type;
 
     /* If there are any preferred connection parameters, set them now */
-    if ( (p_dev_rec->conn_params.min_conn_int     >= BTM_BLE_CONN_INT_MIN ) &&
+    if ( (p_dev_rec->conn_params.min_conn_int     >= BLE_CONN_INT_MIN_HOST_CHECK ) &&
             (p_dev_rec->conn_params.min_conn_int     <= BTM_BLE_CONN_INT_MAX ) &&
-            (p_dev_rec->conn_params.max_conn_int     >= BTM_BLE_CONN_INT_MIN ) &&
+            (p_dev_rec->conn_params.max_conn_int     >= BLE_CONN_INT_MIN_HOST_CHECK ) &&
             (p_dev_rec->conn_params.max_conn_int     <= BTM_BLE_CONN_INT_MAX ) &&
             (p_dev_rec->conn_params.slave_latency    <= BTM_BLE_CONN_LATENCY_MAX ) &&
             (p_dev_rec->conn_params.supervision_tout >= BTM_BLE_CONN_SUP_TOUT_MIN) &&
@@ -762,8 +762,8 @@ void l2cble_process_sig_cmd (tL2C_LCB *p_lcb, UINT8 *p, UINT16 pkt_len)
         STREAM_TO_UINT16 (timeout, p);  /* 0x000A - 0x0C80 */
         /* If we are a master, the slave wants to update the parameters */
         if (p_lcb->link_role == HCI_ROLE_MASTER) {
-            if (min_interval < BTM_BLE_CONN_INT_MIN || min_interval > BTM_BLE_CONN_INT_MAX ||
-                    max_interval < BTM_BLE_CONN_INT_MIN || max_interval > BTM_BLE_CONN_INT_MAX ||
+            if (min_interval < BLE_CONN_INT_MIN_HOST_CHECK || min_interval > BTM_BLE_CONN_INT_MAX ||
+                    max_interval < BLE_CONN_INT_MIN_HOST_CHECK || max_interval > BTM_BLE_CONN_INT_MAX ||
                     latency  > BTM_BLE_CONN_LATENCY_MAX ||
                     timeout < BTM_BLE_CONN_SUP_TOUT_MIN || timeout > BTM_BLE_CONN_SUP_TOUT_MAX ||
                     /* The supervision_timeout parameter defines the link supervision timeout for the connection.