diff --git a/components/spi_flash/esp_flash_spi_init.c b/components/spi_flash/esp_flash_spi_init.c
index d72a388662..69a516a095 100644
--- a/components/spi_flash/esp_flash_spi_init.c
+++ b/components/spi_flash/esp_flash_spi_init.c
@@ -145,7 +145,7 @@ esp_err_t spi_bus_add_flash_device(esp_flash_t **out_chip, const esp_flash_spi_d
         goto fail;
     }
 
-    int dev_id;
+    int dev_id = -1;
     esp_err_t err = esp_flash_init_os_functions(chip, config->host_id, &dev_id);
     if (err == ESP_ERR_NOT_SUPPORTED) {
         ESP_LOGE(TAG, "Init os functions failed! No free CS.");
@@ -156,6 +156,12 @@ esp_err_t spi_bus_add_flash_device(esp_flash_t **out_chip, const esp_flash_spi_d
         ret = err;
         goto fail;
     }
+    // When `CONFIG_SPI_FLASH_SHARE_SPI1_BUS` is not enabled on SPI1 bus, the
+    // `esp_flash_init_os_functions` will not be able to assign a new device ID. In this case, we
+    // use the `cs_id` in the config structure.
+    if (dev_id == -1 && config->host_id == SPI_HOST) {
+        dev_id = config->cs_id;
+    }
     assert(dev_id < SOC_SPI_PERIPH_CS_NUM(config->host_id) && dev_id >= 0);
 
     bool use_iomux = spicommon_bus_using_iomux(config->host_id);
diff --git a/components/spi_flash/include/esp_flash_spi_init.h b/components/spi_flash/include/esp_flash_spi_init.h
index f3ac315eeb..85334d3ea5 100644
--- a/components/spi_flash/include/esp_flash_spi_init.h
+++ b/components/spi_flash/include/esp_flash_spi_init.h
@@ -28,8 +28,12 @@ typedef struct {
     esp_flash_io_mode_t io_mode;    ///< IO mode to read from the Flash
     esp_flash_speed_t speed;        ///< Speed of the Flash clock
     int input_delay_ns;             ///< Input delay of the data pins, in ns. Set to 0 if unknown.
-
-    int cs_id;                      ///< @deprecated CS pin (signal) to use
+    /**
+     * CS line ID, ignored when not `host_id` is not SPI1_HOST, or
+     * `CONFIG_SPI_FLASH_SHARE_SPI1_BUS` is enabled. In this case, the CS line used is
+     * automatically assigned by the SPI bus lock.
+     */
+    int cs_id;
 } esp_flash_spi_device_config_t;
 
 /**
diff --git a/components/spi_flash/spi_flash_os_func_app.c b/components/spi_flash/spi_flash_os_func_app.c
index 07b8778aa5..f6cc038744 100644
--- a/components/spi_flash/spi_flash_os_func_app.c
+++ b/components/spi_flash/spi_flash_os_func_app.c
@@ -127,14 +127,30 @@ static const esp_flash_os_functions_t esp_flash_spi23_default_os_functions = {
     .delay_ms = delay_ms,
 };
 
-esp_err_t esp_flash_init_os_functions(esp_flash_t *chip, int host_id, int* out_dev_id)
+static spi_bus_lock_dev_handle_t register_dev(int host_id)
 {
     spi_bus_lock_handle_t lock = spi_bus_lock_get_by_id(host_id);
     spi_bus_lock_dev_handle_t dev_handle;
     spi_bus_lock_dev_config_t config = {.flags = SPI_BUS_LOCK_DEV_FLAG_CS_REQUIRED};
     esp_err_t err = spi_bus_lock_register_dev(lock, &config, &dev_handle);
     if (err != ESP_OK) {
-        return err;
+        return NULL;
+    }
+    return dev_handle;
+}
+
+esp_err_t esp_flash_init_os_functions(esp_flash_t *chip, int host_id, int* out_dev_id)
+{
+    spi_bus_lock_dev_handle_t dev_handle = NULL;
+
+    // Skip initializing the bus lock when the bus is SPI1 and the bus is not shared with SPI Master
+    // driver, leaving dev_handle = NULL
+    bool skip_register_dev = (host_id == SPI_HOST);
+#if CONFIG_SPI_FLASH_SHARE_SPI1_BUS
+    skip_register_dev = false;
+#endif
+    if (!skip_register_dev) {
+        dev_handle = register_dev(host_id);
     }
 
     if (host_id == SPI1_HOST) {
@@ -166,7 +182,10 @@ esp_err_t esp_flash_init_os_functions(esp_flash_t *chip, int host_id, int* out_d
         return ESP_ERR_INVALID_ARG;
     }
 
-    *out_dev_id = spi_bus_lock_get_dev_id(dev_handle);
+    // Bus lock not initialized, the device ID should be directly given by application.
+    if (dev_handle) {
+        *out_dev_id = spi_bus_lock_get_dev_id(dev_handle);
+    }
 
     return ESP_OK;
 }
@@ -174,7 +193,11 @@ esp_err_t esp_flash_init_os_functions(esp_flash_t *chip, int host_id, int* out_d
 esp_err_t esp_flash_deinit_os_functions(esp_flash_t* chip)
 {
     if (chip->os_func_data) {
-        spi_bus_lock_unregister_dev(((app_func_arg_t*)chip->os_func_data)->dev_lock);
+        spi_bus_lock_dev_handle_t dev_lock = ((app_func_arg_t*)chip->os_func_data)->dev_lock;
+        // SPI bus lock is possible not used on SPI1 bus
+        if (dev_lock) {
+            spi_bus_lock_unregister_dev(dev_lock);
+        }
         free(chip->os_func_data);
     }
     chip->os_func = NULL;