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+# ES24N IOM Configuration Tool
+
+A single-file interactive CLI tool for configuring network settings and updating firmware on TrueNAS ES24N expansion shelf IOM (I/O Module) controllers.
+
+## Requirements
+
+- Python 3 (standard library only — no external dependencies)
+- A USB serial cable connected from the ES24N IOM1 port to the active TrueNAS controller
+- Root or serial device group permissions
+
+## Usage
+
+```bash
+python3 es24n_conf.py
+```
+
+If the serial device is inaccessible, re-run with `sudo`:
+
+```bash
+sudo python3 es24n_conf.py
+```
+
+## Features
+
+### Network Configuration
+
+Connects to the IOM over a USB serial connection and configures each IOM's management network interface via the Redfish API.
+
+- Supports both **Static IP** and **DHCP** configuration
+- Configures IOM1 and IOM2 independently in a single session
+- Displays current network settings before making any changes
+
+### Firmware Updates
+
+Connects to each IOM directly over the network (not serial) and updates IOM and/or Fabric Card firmware via the Redfish API.
+
+- Update IOM firmware, Fabric Card firmware, or both
+- Displays current firmware versions before and after the update
+- Polls update task progress automatically
+
+## Workflow
+
+### Configure a Shelf
+
+1. Connect the serial cable from the ES24N IOM1 port to the controller's USB port
+2. Run the tool and select **Configure a new ES24N shelf**
+3. The tool detects the serial device, opens the connection, and prompts for the BMC admin password
+4. Current network settings for IOM1 and IOM2 are displayed
+5. Choose to apply a new Static IP or DHCP configuration, or leave settings unchanged
+6. Changes are applied via Redfish PATCH requests over the serial loopback (`127.0.0.1`)
+
+### Update Firmware
+
+1. Ensure this system has network access to the IOM management interfaces
+2. Run the tool and select **Update IOM / Fabric Card Firmware**
+3. Enter the admin password and IP addresses for IOM1 and IOM2
+4. Select what to update and provide the firmware file path(s)
+5. The tool uploads, applies, and monitors each update, then restarts the affected components
+
+> **HA Systems:** Update the passive IOM first. After updating both IOMs on one controller, initiate a TrueNAS failover and re-run the tool for the other controller.
+
+## Notes
+
+- Setting a static IP requires two sequential Redfish PATCH requests due to a known ES24N firmware bug. The tool handles this automatically.
+- Firmware uploads are performed over the network — uploading over the 115200-baud serial connection would be impractically slow.
+- After applying network changes, verify each expander appears in TrueNAS under **System Settings > Enclosure > NVMe-oF Expansion Shelves** before disconnecting the serial cable.