diff --git a/ChangeLog b/ChangeLog
index 5c0de5a968..c787d1a1e9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -6,6 +6,7 @@
             Ensure eval("1;;;")==1 - eval("1;")==1 before, but not eval("1;;")            
             Ensure AssignmentExpr returns the value of LHS, not the LHS. `(a=2)=3` now fails (as per spec)
             Ensure default args for arrow functions fail with error `(a,b=3)=>a+b` now fails (until default args get added)
+            nRF52: bootloader asks for connection interval 7.5->30ms now, not just 15ms. Should improve DFU on iOS 16 which doesn't honour 15ms request
 
      2v19 : Fix Object.values/entries for numeric keys after 2v18 regression (fix #2375)
             nRF52: for SD>5 use static buffers for advertising and scan response data (#2367)
diff --git a/targetlibs/nrf5x_12/components/libraries/bootloader/ble_dfu/nrf_ble_dfu.c b/targetlibs/nrf5x_12/components/libraries/bootloader/ble_dfu/nrf_ble_dfu.c
index ef0c7ad96e..e3d3f675ce 100644
--- a/targetlibs/nrf5x_12/components/libraries/bootloader/ble_dfu/nrf_ble_dfu.c
+++ b/targetlibs/nrf5x_12/components/libraries/bootloader/ble_dfu/nrf_ble_dfu.c
@@ -1,30 +1,30 @@
 /**
  * Copyright (c) 2016 - 2017, Nordic Semiconductor ASA
- * 
+ *
  * All rights reserved.
- * 
+ *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
- * 
+ *
  * 1. Redistributions of source code must retain the above copyright notice, this
  *    list of conditions and the following disclaimer.
- * 
+ *
  * 2. Redistributions in binary form, except as embedded into a Nordic
  *    Semiconductor ASA integrated circuit in a product or a software update for
  *    such product, must reproduce the above copyright notice, this list of
  *    conditions and the following disclaimer in the documentation and/or other
  *    materials provided with the distribution.
- * 
+ *
  * 3. Neither the name of Nordic Semiconductor ASA nor the names of its
  *    contributors may be used to endorse or promote products derived from this
  *    software without specific prior written permission.
- * 
+ *
  * 4. This software, with or without modification, must only be used with a
  *    Nordic Semiconductor ASA integrated circuit.
- * 
+ *
  * 5. Any software provided in binary form under this license must not be reverse
  *    engineered, decompiled, modified and/or disassembled.
- * 
+ *
  * THIS SOFTWARE IS PROVIDED BY NORDIC SEMICONDUCTOR ASA "AS IS" AND ANY EXPRESS
  * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY, NONINFRINGEMENT, AND FITNESS FOR A PARTICULAR PURPOSE ARE
@@ -35,7 +35,7 @@
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- * 
+ *
  */
 
 #include "nrf_ble_dfu.h"
@@ -143,7 +143,7 @@ static uint32_t conn_params_init(void)
 /**@brief     Function for the Advertising functionality initialization.
  *
  * @details   Encodes the required advertising data and passes it to the stack.
- *            The advertising data encoded here is specific for DFU. 
+ *            The advertising data encoded here is specific for DFU.
  *            Setting advertising data can by done by calling @ref ble_advdata_set.
  */
 static uint32_t advertising_init(uint8_t adv_flags)
@@ -154,12 +154,12 @@ static uint32_t advertising_init(uint8_t adv_flags)
     uint16_t    actual_device_name_length   = max_device_name_length;
 
     uint8_t     p_encoded_advdata[MAX_ADV_DATA_LENGTH];
-    
+
     // Encode flags.
     p_encoded_advdata[0]                    = 0x2;
     p_encoded_advdata[1]                    = BLE_GAP_AD_TYPE_FLAGS;
     p_encoded_advdata[2]                    = adv_flags;
-    
+
     // Encode 'more available' uuid list.
     p_encoded_advdata[3]                    = 0x3;
     p_encoded_advdata[4]                    = BLE_GAP_AD_TYPE_16BIT_SERVICE_UUID_MORE_AVAILABLE;
@@ -172,7 +172,7 @@ static uint32_t advertising_init(uint8_t adv_flags)
     {
         return err_code;
     }
-    
+
     // Set GAP device in advertising data.
     if (actual_device_name_length <= max_device_name_length)
     {
@@ -524,7 +524,7 @@ static bool on_rw_authorize_req(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
     ble_gatts_rw_authorize_reply_params_t   auth_reply = {0};
     ble_gatts_evt_rw_authorize_request_t  * p_authorize_request;
     ble_gatts_evt_write_t                 * p_ble_write_evt;
-    
+
     p_authorize_request = &(p_ble_evt->evt.gatts_evt.params.authorize_request);
     p_ble_write_evt = &(p_ble_evt->evt.gatts_evt.params.authorize_request.request.write);
 
@@ -544,7 +544,7 @@ static bool on_rw_authorize_req(ble_dfu_t * p_dfu, ble_evt_t * p_ble_evt)
         {
             // Send an error response to the peer indicating that the CCCD is improperly configured.
             auth_reply.params.write.gatt_status = BLE_GATT_STATUS_ATTERR_CPS_CCCD_CONFIG_ERROR;
- 
+
             // Ignore response of auth reply
             (void)sd_ble_gatts_rw_authorize_reply(m_conn_handle, &auth_reply);
             return false;
@@ -660,9 +660,9 @@ static void on_ble_evt(ble_evt_t * p_ble_evt)
             {
                 if (on_rw_authorize_req(&m_dfu, p_ble_evt))
                 {
-                    err_code = on_ctrl_pt_write(&m_dfu, 
+                    err_code = on_ctrl_pt_write(&m_dfu,
                            &(p_ble_evt->evt.gatts_evt.params.authorize_request.request.write));
-#ifdef NRF_DFU_DEBUG_VERSION  
+#ifdef NRF_DFU_DEBUG_VERSION
                     if (err_code != NRF_SUCCESS)
                     {
                         NRF_LOG_ERROR("Could not handle on_ctrl_pt_write. err_code: 0x%04x\r\n", err_code);
@@ -684,19 +684,19 @@ static void on_ble_evt(ble_evt_t * p_ble_evt)
             err_code = sd_ble_gatts_sys_attr_set(p_ble_evt->evt.gap_evt.conn_handle, NULL, 0, 0);
             APP_ERROR_CHECK(err_code);
             break;
-        
+
         case BLE_GATTS_EVT_WRITE:
             on_write(&m_dfu, p_ble_evt);
             break;
 
 #if (NRF_SD_BLE_API_VERSION == 3)
         case BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST:
-            err_code = sd_ble_gatts_exchange_mtu_reply(p_ble_evt->evt.gatts_evt.conn_handle, 
+            err_code = sd_ble_gatts_exchange_mtu_reply(p_ble_evt->evt.gatts_evt.conn_handle,
                                                        NRF_BLE_MAX_MTU_SIZE);
             APP_ERROR_CHECK(err_code);
             break; // BLE_GATTS_EVT_EXCHANGE_MTU_REQUEST
 #endif
-        
+
         default:
             // No implementation needed.
             break;
@@ -771,8 +771,8 @@ static uint32_t gap_params_init(void)
                                           strlen(DEVICE_NAME));
     VERIFY_SUCCESS(err_code);
 
-    gap_conn_params.min_conn_interval = MIN_CONN_INTERVAL;
-    gap_conn_params.max_conn_interval = MAX_CONN_INTERVAL;
+    gap_conn_params.min_conn_interval = NRF_DFU_BLE_MIN_CONN_INTERVAL;
+    gap_conn_params.max_conn_interval = NRF_DFU_BLE_MAX_CONN_INTERVAL;
     gap_conn_params.slave_latency     = SLAVE_LATENCY;
     gap_conn_params.conn_sup_timeout  = CONN_SUP_TIMEOUT;
 
@@ -809,8 +809,8 @@ static uint32_t ble_stack_init(bool init_softdevice)
 
 #if (NRF_SD_BLE_API_VERSION == 3)
     ble_enable_params.gatt_enable_params.att_mtu = NRF_BLE_MAX_MTU_SIZE;
-#endif    
-    
+#endif
+
     // Enable BLE stack.
     err_code = softdevice_enable(&ble_enable_params);
     return err_code;
diff --git a/targets/nrf5x/bluetooth.c b/targets/nrf5x/bluetooth.c
index 72dd64cdb7..2adeec919e 100644
--- a/targets/nrf5x/bluetooth.c
+++ b/targets/nrf5x/bluetooth.c
@@ -923,6 +923,7 @@ nrf_log_module_dynamic_data_t NRF_LOG_MODULE_DATA_DYNAMIC = {
 
 /// Function for handling an event from the Connection Parameters Module.
 static void on_conn_params_evt(ble_conn_params_evt_t * p_evt) {
+  // Either BLE_CONN_PARAMS_EVT_FAILED or BLE_CONN_PARAMS_EVT_SUCCEEDED - that's it
 }
 
 /// Sigh - NFC has lots of these, so we need to define it to build
diff --git a/targets/nrf5x_dfu/sdk12/sdk_config.h b/targets/nrf5x_dfu/sdk12/sdk_config.h
index 9c0848eb56..b8f49a373d 100644
--- a/targets/nrf5x_dfu/sdk12/sdk_config.h
+++ b/targets/nrf5x_dfu/sdk12/sdk_config.h
@@ -6,7 +6,7 @@
 #ifdef USE_APP_CONFIG
 #include "app_config.h"
 #endif
-// <h> nRF_Drivers 
+// <h> nRF_Drivers
 
 //==========================================================
 // <e> CLOCK_ENABLED - nrf_drv_clock - CLOCK peripheral driver
@@ -16,35 +16,35 @@
 #endif
 #if  CLOCK_ENABLED
 // <o> CLOCK_CONFIG_XTAL_FREQ  - HF XTAL Frequency
- 
-// <0=> Default (64 MHz) 
+
+// <0=> Default (64 MHz)
 
 #ifndef CLOCK_CONFIG_XTAL_FREQ
 #define CLOCK_CONFIG_XTAL_FREQ 0
 #endif
 
 // <o> CLOCK_CONFIG_LF_SRC  - LF Clock Source
- 
-// <0=> RC 
-// <1=> XTAL 
-// <2=> Synth 
+
+// <0=> RC
+// <1=> XTAL
+// <2=> Synth
 
 #ifndef CLOCK_CONFIG_LF_SRC
 #define CLOCK_CONFIG_LF_SRC 1
 #endif
 
 // <o> CLOCK_CONFIG_IRQ_PRIORITY  - Interrupt priority
- 
+
 
 // <i> Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
-// <0=> 0 (highest) 
-// <1=> 1 
-// <2=> 2 
-// <3=> 3 
-// <4=> 4 
-// <5=> 5 
-// <6=> 6 
-// <7=> 7 
+// <0=> 0 (highest)
+// <1=> 1
+// <2=> 2
+// <3=> 3
+// <4=> 4
+// <5=> 5
+// <6=> 6
+// <7=> 7
 
 #ifndef CLOCK_CONFIG_IRQ_PRIORITY
 #define CLOCK_CONFIG_IRQ_PRIORITY 6
@@ -54,7 +54,7 @@
 // </e>
 
 // <q> PERIPHERAL_RESOURCE_SHARING_ENABLED  - nrf_drv_common - Peripheral drivers common module
- 
+
 
 #ifndef PERIPHERAL_RESOURCE_SHARING_ENABLED
 #define PERIPHERAL_RESOURCE_SHARING_ENABLED 0
@@ -67,29 +67,29 @@
 #endif
 #if  RNG_ENABLED
 // <q> RNG_CONFIG_ERROR_CORRECTION  - Error correction
- 
+
 
 #ifndef RNG_CONFIG_ERROR_CORRECTION
 #define RNG_CONFIG_ERROR_CORRECTION 0
 #endif
 
-// <o> RNG_CONFIG_POOL_SIZE - Pool size 
+// <o> RNG_CONFIG_POOL_SIZE - Pool size
 #ifndef RNG_CONFIG_POOL_SIZE
 #define RNG_CONFIG_POOL_SIZE 32
 #endif
 
 // <o> RNG_CONFIG_IRQ_PRIORITY  - Interrupt priority
- 
+
 
 // <i> Priorities 0,2 (nRF51) and 0,1,4,5 (nRF52) are reserved for SoftDevice
-// <0=> 0 (highest) 
-// <1=> 1 
-// <2=> 2 
-// <3=> 3 
-// <4=> 4 
-// <5=> 5 
-// <6=> 6 
-// <7=> 7 
+// <0=> 0 (highest)
+// <1=> 1
+// <2=> 2
+// <3=> 3
+// <4=> 4
+// <5=> 5
+// <6=> 6
+// <7=> 7
 
 #ifndef RNG_CONFIG_IRQ_PRIORITY
 #define RNG_CONFIG_IRQ_PRIORITY 6
@@ -98,14 +98,14 @@
 #endif //RNG_ENABLED
 // </e>
 
-// </h> 
+// </h>
 //==========================================================
 
-// <h> nRF_Libraries 
+// <h> nRF_Libraries
 
 //==========================================================
 // <q> APP_FIFO_ENABLED  - app_fifo - Software FIFO implementation
- 
+
 
 #ifndef APP_FIFO_ENABLED
 #define APP_FIFO_ENABLED 1
@@ -118,14 +118,14 @@
 #endif
 #if  APP_SCHEDULER_ENABLED
 // <q> APP_SCHEDULER_WITH_PAUSE  - Enabling pause feature
- 
+
 
 #ifndef APP_SCHEDULER_WITH_PAUSE
 #define APP_SCHEDULER_WITH_PAUSE 0
 #endif
 
 // <q> APP_SCHEDULER_WITH_PROFILER  - Enabling scheduler profiling
- 
+
 
 #ifndef APP_SCHEDULER_WITH_PROFILER
 #define APP_SCHEDULER_WITH_PROFILER 0
@@ -141,14 +141,14 @@
 #endif
 #if  APP_TIMER_ENABLED
 // <q> APP_TIMER_WITH_PROFILER  - Enable app_timer profiling
- 
+
 
 #ifndef APP_TIMER_WITH_PROFILER
 #define APP_TIMER_WITH_PROFILER 0
 #endif
 
 // <q> APP_TIMER_KEEPS_RTC_ACTIVE  - Enable RTC always on
- 
+
 
 // <i> If option is enabled RTC is kept running even if there is no active timers.
 // <i> This option can be used when app_timer is used for timestamping.
@@ -161,14 +161,14 @@
 // </e>
 
 // <q> CRC32_ENABLED  - crc32 - CRC32 calculation routines
- 
+
 
 #ifndef CRC32_ENABLED
 #define CRC32_ENABLED 1
 #endif
 
 // <q> ECC_ENABLED  - ecc - Elliptic Curve Cryptography Library
- 
+
 
 #ifndef ECC_ENABLED
 #define ECC_ENABLED 0
@@ -180,7 +180,7 @@
 #define FSTORAGE_ENABLED 1
 #endif
 #if  FSTORAGE_ENABLED
-// <o> FS_QUEUE_SIZE - Configures the size of the internal queue. 
+// <o> FS_QUEUE_SIZE - Configures the size of the internal queue.
 // <i> Increase this if there are many users, or if it is likely that many
 // <i> operation will be queued at once without waiting for the previous operations
 // <i> to complete. In general, increase the queue size if you frequently receive
@@ -190,7 +190,7 @@
 #define FS_QUEUE_SIZE 4
 #endif
 
-// <o> FS_OP_MAX_RETRIES - Number attempts to execute an operation if the SoftDevice fails. 
+// <o> FS_OP_MAX_RETRIES - Number attempts to execute an operation if the SoftDevice fails.
 // <i> Increase this value if events return the @ref FS_ERR_OPERATION_TIMEOUT
 // <i> error often. The SoftDevice may fail to schedule flash access due to high BLE activity.
 
@@ -198,7 +198,7 @@
 #define FS_OP_MAX_RETRIES 3
 #endif
 
-// <o> FS_MAX_WRITE_SIZE_WORDS - Maximum number of words to be written to flash in a single operation. 
+// <o> FS_MAX_WRITE_SIZE_WORDS - Maximum number of words to be written to flash in a single operation.
 // <i> Tweaking this value can increase the chances of the SoftDevice being
 // <i> able to fit flash operations in between radio activity. This value is bound by the
 // <i> maximum number of words which the SoftDevice can write to flash in a single call to
@@ -217,17 +217,17 @@
 #define HCI_MEM_POOL_ENABLED 1
 #endif
 #if  HCI_MEM_POOL_ENABLED
-// <o> HCI_TX_BUF_SIZE - TX buffer size in bytes. 
+// <o> HCI_TX_BUF_SIZE - TX buffer size in bytes.
 #ifndef HCI_TX_BUF_SIZE
 #define HCI_TX_BUF_SIZE 600
 #endif
 
-// <o> HCI_RX_BUF_SIZE - RX buffer size in bytes. 
+// <o> HCI_RX_BUF_SIZE - RX buffer size in bytes.
 #ifndef HCI_RX_BUF_SIZE
 #define HCI_RX_BUF_SIZE 600
 #endif
 
-// <o> HCI_RX_BUF_QUEUE_SIZE - RX buffer queue size. 
+// <o> HCI_RX_BUF_QUEUE_SIZE - RX buffer queue size.
 #ifndef HCI_RX_BUF_QUEUE_SIZE
 #define HCI_RX_BUF_QUEUE_SIZE 4
 #endif
@@ -235,10 +235,10 @@
 #endif //HCI_MEM_POOL_ENABLED
 // </e>
 
-// </h> 
+// </h>
 
 // <q> NRF_QUEUE_ENABLED  - nrf_queue - Queue module
- 
+
 
 #ifndef NRF_QUEUE_ENABLED
 #define NRF_QUEUE_ENABLED 1
@@ -246,7 +246,7 @@
 
 //==========================================================
 
-// <h> nRF_Log 
+// <h> nRF_Log
 
 //==========================================================
 // <e> NRF_LOG_ENABLED - nrf_log - Logging
@@ -262,48 +262,48 @@
 #endif
 #if  NRF_LOG_USES_COLORS
 // <o> NRF_LOG_COLOR_DEFAULT  - ANSI escape code prefix.
- 
-// <0=> Default 
-// <1=> Black 
-// <2=> Red 
-// <3=> Green 
-// <4=> Yellow 
-// <5=> Blue 
-// <6=> Magenta 
-// <7=> Cyan 
-// <8=> White 
+
+// <0=> Default
+// <1=> Black
+// <2=> Red
+// <3=> Green
+// <4=> Yellow
+// <5=> Blue
+// <6=> Magenta
+// <7=> Cyan
+// <8=> White
 
 #ifndef NRF_LOG_COLOR_DEFAULT
 #define NRF_LOG_COLOR_DEFAULT 0
 #endif
 
 // <o> NRF_LOG_ERROR_COLOR  - ANSI escape code prefix.
- 
-// <0=> Default 
-// <1=> Black 
-// <2=> Red 
-// <3=> Green 
-// <4=> Yellow 
-// <5=> Blue 
-// <6=> Magenta 
-// <7=> Cyan 
-// <8=> White 
+
+// <0=> Default
+// <1=> Black
+// <2=> Red
+// <3=> Green
+// <4=> Yellow
+// <5=> Blue
+// <6=> Magenta
+// <7=> Cyan
+// <8=> White
 
 #ifndef NRF_LOG_ERROR_COLOR
 #define NRF_LOG_ERROR_COLOR 0
 #endif
 
 // <o> NRF_LOG_WARNING_COLOR  - ANSI escape code prefix.
- 
-// <0=> Default 
-// <1=> Black 
-// <2=> Red 
-// <3=> Green 
-// <4=> Yellow 
-// <5=> Blue 
-// <6=> Magenta 
-// <7=> Cyan 
-// <8=> White 
+
+// <0=> Default
+// <1=> Black
+// <2=> Red
+// <3=> Green
+// <4=> Yellow
+// <5=> Blue
+// <6=> Magenta
+// <7=> Cyan
+// <8=> White
 
 #ifndef NRF_LOG_WARNING_COLOR
 #define NRF_LOG_WARNING_COLOR 0
@@ -313,12 +313,12 @@
 // </e>
 
 // <o> NRF_LOG_DEFAULT_LEVEL  - Default Severity level
- 
-// <0=> Off 
-// <1=> Error 
-// <2=> Warning 
-// <3=> Info 
-// <4=> Debug 
+
+// <0=> Off
+// <1=> Error
+// <2=> Warning
+// <3=> Info
+// <4=> Debug
 
 #ifndef NRF_LOG_DEFAULT_LEVEL
 #define NRF_LOG_DEFAULT_LEVEL 3
@@ -332,7 +332,7 @@
 #define NRF_LOG_DEFERRED 1
 #endif
 #if  NRF_LOG_DEFERRED
-// <o> NRF_LOG_DEFERRED_BUFSIZE - Size of the buffer for logs in words. 
+// <o> NRF_LOG_DEFERRED_BUFSIZE - Size of the buffer for logs in words.
 // <i> Must be power of 2
 
 #ifndef NRF_LOG_DEFERRED_BUFSIZE
@@ -343,7 +343,7 @@
 // </e>
 
 // <q> NRF_LOG_USES_TIMESTAMP  - Enable timestamping
- 
+
 
 // <i> Function for getting the timestamp is provided by the user
 
@@ -354,8 +354,29 @@
 #endif //NRF_LOG_ENABLED
 // </e>
 
-// </h> 
+// </h>
+
+//==========================================================
+
+// <h> BLE DFU connection
+
 //==========================================================
+// <o> NRF_DFU_BLE_MIN_CONN_INTERVAL - Minimum connection interval (units).
+// <i> Minimum GAP connection interval, in 1.25 ms units.
+
+#ifndef NRF_DFU_BLE_MIN_CONN_INTERVAL
+#define NRF_DFU_BLE_MIN_CONN_INTERVAL 6 // 7.5ms
+#endif
+
+// <o> NRF_DFU_BLE_MAX_CONN_INTERVAL - Maximum connection interval (units).
+// <i> Maximum GAP connection interval, in 1.25 ms units.
+
+#ifndef NRF_DFU_BLE_MAX_CONN_INTERVAL
+#define NRF_DFU_BLE_MAX_CONN_INTERVAL 24 // 30ms
+#endif
+
+// </h>
+
 
 // <<< end of configuration section >>>
 #endif //SDK_CONFIG_H
diff --git a/targets/nrf5x_dfu/sdk15/sdk_config.h b/targets/nrf5x_dfu/sdk15/sdk_config.h
index 7e6ac2613a..1a6f04cd14 100644
--- a/targets/nrf5x_dfu/sdk15/sdk_config.h
+++ b/targets/nrf5x_dfu/sdk15/sdk_config.h
@@ -981,14 +981,14 @@
 // <i> Minimum GAP connection interval, in 1.25 ms units.
 
 #ifndef NRF_DFU_BLE_MIN_CONN_INTERVAL
-#define NRF_DFU_BLE_MIN_CONN_INTERVAL 12
+#define NRF_DFU_BLE_MIN_CONN_INTERVAL 6 // 7.5ms
 #endif
 
 // <o> NRF_DFU_BLE_MAX_CONN_INTERVAL - Maximum connection interval (units).
 // <i> Maximum GAP connection interval, in 1.25 ms units.
 
 #ifndef NRF_DFU_BLE_MAX_CONN_INTERVAL
-#define NRF_DFU_BLE_MAX_CONN_INTERVAL 12
+#define NRF_DFU_BLE_MAX_CONN_INTERVAL 24 // 30ms
 #endif
 
 // <o> NRF_DFU_BLE_CONN_SUP_TIMEOUT_MS - Supervision timeout (ms).