> For the complete documentation index, see [llms.txt](https://help.iodd.kr/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://help.iodd.kr/basic-control-function-keys.md).

# Basic Control / Function Keys

The physical keys on IODD devices control file navigation, ISO/VHD mounting, write protection, safe removal, voltage checks, and firmware recovery. This guide covers keypad models such as ST400, ST300, MINI PRO, MINI, LK100, plus legacy 2531 jog dial and 2541 touch key operation.

## IODD ST300/400, MINI PRO, MINI (Legacy)

The physical keypad on your IODD allows for quick navigation and advanced power-user shortcuts. Understanding these keys will significantly improve your workflow.

### 1. Basic Control (Press Key Once)

#### ⌨️ For Models with Keypad (ST300/400, MINI PRO, MINI, LK100)

| Key                                                                                                                      | Function    | Description                                                    |
| ------------------------------------------------------------------------------------------------------------------------ | ----------- | -------------------------------------------------------------- |
| <p><img src="/files/MR6TpsEdEpCHdwqDG47Y" alt="IODD key 1" data-size="original"></p><p><strong>\[1]</strong></p>         | **Rescan**  | Rescans the root folder for new files.                         |
| <p><img src="/files/cB683jSVBXhak23059V5" alt="IODD key 2" data-size="original"></p><p><strong>\[2]</strong></p>         | **Up**      | Moves up in the file or item list.                             |
| <p><img src="/files/ejknFAVleTS00OmGmJTP" alt="IODD key 3" data-size="original"></p><p><strong>\[3]</strong></p>         | **Voltage** | Displays the **VBUS minimum voltage** (Crucial for stability). |
| <p><img src="/files/MUnE4f22Td5N2t6GifmB" alt="IODD key 4" data-size="original"></p><p><strong>\[4]</strong></p>         | **Back**    | Goes to the parent folder.                                     |
| <p><img src="/files/uNTxDxwvqJOZQIWmFQmH" alt="IODD key 5" data-size="original"></p><p><strong>\[5]</strong></p>         | **Info**    | View detailed file information (size, fragmentation, etc.).    |
| <p><img src="/files/qoECH5fRwdzrMrtobrrg" alt="IODD key 6" data-size="original"></p><p><strong>\[6]</strong></p>         | **Select**  | Selects a file to mount or enters a folder.                    |
| <p><img src="/files/J8W3B6lF7p0bDH3AwnUh" alt="IODD key 7" data-size="original"></p><p><strong>\[7]</strong></p>         | **Eject**   | Ejects the most recently mounted virtual drive.                |
| <p><img src="/files/YyA7oAH99iBV4QLj4CDG" alt="IODD key 8" data-size="original"></p><p><strong>\[8]</strong></p>         | **Down**    | Moves down in the file or item list.                           |
| <p><img src="/files/buAgU1CaJyHuMYigI5Fq" alt="IODD key 9" data-size="original"></p><p><strong>\[9]</strong></p>         | **Save**    | Saves the current mount state (Auto-mounts on next boot).      |
| <p><img src="/files/0oGOlwTGucTb0Emg6DCf" alt="IODD menu key" data-size="original"></p><p><strong>\[M]</strong></p>      | **Menu**    | Enters or exits the system settings menu.                      |
| <p><img src="/files/ZIhyUoLkA6faAaQq6gku" alt="IODD key 0" data-size="original"></p><p><strong>\[0]</strong></p>         | **Help**    | Accesses the built-in Help menu or active error details.       |
| <p><img src="/files/72xk15vH1VIDBp3y2Gi0" alt="IODD Enter key" data-size="original"></p><p><strong>\[Enter]</strong></p> | **Select**  | Same function as Key \[6].                                     |

### 2. Advanced Hotkeys (Long Press - 3 Seconds)

For the **ST300/400, MINI PRO, MINI (Legacy)**, holding a key for 3 seconds triggers advanced maintenance functions:

| Key      | Function            | Description                                                                     |
| -------- | ------------------- | ------------------------------------------------------------------------------- |
| **\[1]** | **Reconnect**       | Restarts the USB connection without physical removal.                           |
| **\[3]** | **WP Reconnect**    | Reconnects with **Write-Protection** enabled for all drives.                    |
| **\[4]** | **Partition List**  | Displays all partitions; allows manual selection of the default data partition. |
| **\[7]** | **Detach All**      | Reconnects with all virtual drives (ISO/VHD/IMA) unmounted.                     |
| **\[9]** | **Sleep Mode**      | Safely detaches the USB connection and enters power-saving sleep mode.          |
| **\[0]** | **Temp Disable WP** | Reconnects with Write-Protection **temporarily disabled**.                      |

### 3. Startup Keys (Hold while connecting USB)

These keys must be held **before and during** the insertion of the USB cable:

| Key                 | Mode / Function       | Description                                                                 |
| ------------------- | --------------------- | --------------------------------------------------------------------------- |
| **\[1]**            | **Factory Reset**     | Resets all settings (LCD bright, standby time, etc.) to defaults.           |
| **\[3]**            | **WP Mode**           | Starts the device in a global Write-Protected state.                        |
| **\[5]**            | **Standalone**        | Operates the IODD using external power without a PC connection.             |
| **\[7]**            | **Unmount All**       | Ensures no virtual drives are loaded upon startup.                          |
| **\[M]**            | **Standalone Menu**   | Enters the system settings menu in Standalone Mode.                         |
| **\[0]**            | **Key Info**          | Displays a list of available startup keys on the screen.                    |
| **\[9] + \[Enter]** | **Firmware Recovery** | **Force Recovery:** Hold both keys for 7s to re-flash the current firmware. |

### For IODD 2531 (Jog Dial)

* **Jog Up/Down**: Moves the cursor through the file list or menu items.
* **Jog Click (Center)**: Selects a file or enters a folder.
* **Back Button (Side)**: Moves to the parent folder or exits the current menu.

### For IODD 2541 (Touch Keys)

The 2541 features a 12-button capacitive touch interface. Operation is identical to the physical keypad models, but requires a light touch rather than a press.

* **\[2] / \[8]**: Up / Down navigation.
* **\[6] / \[Enter]**: Select / Mount.
* **\[4]**: Back / Exit.

***

{% hint style="info" %}
**Correct Startup Sequence**

1. Hold the desired key firmly.
2. Plug in the USB cable.
3. Release the key once the IODD logo appears.
   {% endhint %}

***

### Terminal Verification

```bash
# Monitor kernel messages for USB reconnects/errors
$ dmesg -w | grep -i usb
```


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