docs: update firmware update tool documentation

docs/en/source/camera_devices/5_advanced_guide/advanced_guide.rst

@@ -40,4 +40,5 @@ Configuration & Modes
     configuration/disparity_search_offset.md
     configuration/interleave_ae_mode.md
     configuration/predefined_presets.md
+    configuration/firmware_update_tool.md
     configuration/net_camera.md

docs/en/source/camera_devices/5_advanced_guide/configuration/firmware_update_tool.md

@@ -0,0 +1,34 @@
+# firmware_update_tool
+
+`firmware_update_tool` upgrades device firmware or writes preset files from the ROS 2 command line. Before upgrading, make sure the device connection is stable. When multiple devices are connected, specify the serial number to avoid updating the wrong device.
+
+Show help:
+
+```bash
+ros2 run orbbec_camera firmware_update_tool -- --help
+```
+
+Upgrade firmware for one device:
+
+```bash
+ros2 run orbbec_camera firmware_update_tool -- \
+--serial_number <SN> \
+--firmware_path /path/to/firmware.bin
+```
+
+Write a preset file:
+
+```bash
+ros2 run orbbec_camera firmware_update_tool -- \
+--serial_number <SN> \
+--preset_path /path/to/preset.bin
+```
+
+For batch updates, `--serial_number` accepts comma-separated values. Add `--continue_on_error` if later devices should still be processed after one device fails.
+
+```bash
+ros2 run orbbec_camera firmware_update_tool -- \
+--serial_number SN1,SN2 \
+--firmware_path /path/to/firmware.bin \
+--continue_on_error
+```