diff --git a/project/example/ble/ble_peripheral/app/src/PWM.h b/project/example/ble/ble_peripheral/app/src/PWM.h
index 6db13bd..7c1af7a 100644
--- a/project/example/ble/ble_peripheral/app/src/PWM.h
+++ b/project/example/ble/ble_peripheral/app/src/PWM.h
@@ -147,8 +147,7 @@ void Bridge_Init(void);
 void Bridge_Off(void);
 void Bridge_Service_1ms(void);
 void Bridge_Deadtime_Expired(void);
-uint8_t Bridge_PauseForFlash(void);
-void Bridge_ResumeAfterFlash(uint8_t paused);
+uint8_t Bridge_PrepareFlash(uint8_t *keep_timer3);
 #ifdef __cplusplus
 }
 #endif
diff --git a/project/example/ble/ble_peripheral/app/src/bridge_pwm.c b/project/example/ble/ble_peripheral/app/src/bridge_pwm.c
index 0b3a82c..5be56ef 100644
--- a/project/example/ble/ble_peripheral/app/src/bridge_pwm.c
+++ b/project/example/ble/ble_peripheral/app/src/bridge_pwm.c
@@ -246,26 +246,42 @@ void Bridge_Off(void)
     output_mode = BRIDGE_MODE_OFF;
 }
 
-uint8_t Bridge_PauseForFlash(void)
+uint8_t Bridge_PrepareFlash(uint8_t *keep_timer3)
 {
-    /*
-     * Single-color output is hardware PWM and remains stable while flash
-     * masks interrupts. Dual-color output is Timer3-driven, so force both
-     * bridge inputs low before flash can stretch an active direction pulse.
-     */
-    if (!bridge_ready || output_mode != BRIDGE_MODE_DUAL) {
+    if (keep_timer3 == 0) {
         return 0U;
     }
 
-    Bridge_Off();
-    return 1U;
-}
-
-void Bridge_ResumeAfterFlash(uint8_t paused)
-{
-    if (paused) {
-        Bridge_Service_1ms();
+    *keep_timer3 = 0U;
+    if (!bridge_ready) {
+        return 1U;
     }
+
+    /*
+     * Hardware PWM single-color output needs no interrupt while flash is
+     * busy. A stable dual-color frame may keep Timer3 enabled because its
+     * complete normal interrupt path is located in RAM.
+     */
+    if (output_mode == BRIDGE_MODE_SINGLE &&
+        timer_stage == BRIDGE_STAGE_IDLE) {
+        return 1U;
+    }
+
+    if (output_mode == BRIDGE_MODE_DUAL &&
+        timer_stage >= BRIDGE_STAGE_START_W &&
+        timer_stage <= BRIDGE_STAGE_END_C) {
+        *keep_timer3 = 1U;
+        return 1U;
+    }
+
+    if (output_mode == BRIDGE_MODE_OFF &&
+        timer_stage == BRIDGE_STAGE_IDLE &&
+        W_PWM_duty == 0U && C_PWM_duty == 0U) {
+        return 1U;
+    }
+
+    /* Retry on the next 1 ms task after a bridge mode transition settles. */
+    return 0U;
 }
 
 __RAM_CODE void Bridge_Deadtime_Expired(void)
diff --git a/project/example/ble/ble_peripheral/app/src/ota_flash_interface.c b/project/example/ble/ble_peripheral/app/src/ota_flash_interface.c
index 2a7f87c..232c874 100644
--- a/project/example/ble/ble_peripheral/app/src/ota_flash_interface.c
+++ b/project/example/ble/ble_peripheral/app/src/ota_flash_interface.c
@@ -96,26 +96,53 @@ void ble_flash_handle(void)
 
 uint8_t app_data[FLASH_PAGE_SIZE] = {0};
 
+__RAM_CODE static void app_user_data_flash_commit(uint8_t keep_timer3)
+{
+		uint32_t saved_irq_enable;
+		uint32_t irq_temp;
+		uint32_t live_irq_mask;
+
+		/*
+		 * BLE_Handler executes from chip ROM and PendSV_Handler executes
+		 * from RAM, so Bluetooth timing can remain active while flash is
+		 * busy. The stable dual-color Timer3 path also executes from RAM.
+		 * Block only ordinary XIP-backed peripheral/task interrupts.
+		 */
+		irq_temp = __disable_irq();
+		saved_irq_enable = NVIC->ISER[0];
+		NVIC->ICER[0] = 0xFFFFFFFFUL;
+		live_irq_mask = (1UL << BLE_IRQn);
+		if(keep_timer3)
+			live_irq_mask |= (1UL << TIMER3_IRQn);
+		NVIC->ISER[0] = live_irq_mask;
+		if(!irq_temp)
+			__enable_irq();
+
+		FMC_SPI_Flash_Erase_Page(0x1E000);
+		FMC_SPI_Flash_WritePage(0x1E000, app_data, FLASH_PAGE_SIZE);
+
+		__disable_irq();
+		NVIC->ICER[0] = 0xFFFFFFFFUL;
+		NVIC->ISER[0] = saved_irq_enable;
+		if(!irq_temp)
+			__enable_irq();
+}
+
 //uint16_t app_op_flash_start = 10000;
 void app_op_flash(void)
 {
-		uint8_t bridge_paused;
+		uint8_t keep_timer3;
 
 		if(op_flash.op_state == OP_IDEL&&app_op_flash_flag ==0)
 			{
 				/*
-				 * Commit user data as one transaction. Timer3 cannot advance
-				 * dual-color PWM while flash masks interrupts, so hold the
-				 * H-bridge at 00 and resume from a fresh complete frame.
-				 * Hardware PWM single-color output does not need pausing.
+				 * Wait out a brief bridge mode handoff, then save immediately
+				 * without stopping Bluetooth or the active light waveform.
 				 */
-				GLOBAL_INT_DISABLE();
-				bridge_paused = Bridge_PauseForFlash();
-				FMC_SPI_Flash_Erase_Page(0x1E000);
-				FMC_SPI_Flash_WritePage(0x1E000, app_data, FLASH_PAGE_SIZE);
-				GLOBAL_INT_RESTORE();
+				if(!Bridge_PrepareFlash(&keep_timer3))
+					return;
+				app_user_data_flash_commit(keep_timer3);
 				app_op_flash_flag = 2;
-				Bridge_ResumeAfterFlash(bridge_paused);
 		  }
 			else if(op_flash.op_state == OP_IDEL &&app_op_flash_flag ==1)
 			{