> 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/product-reference-wiki/iodd-2531.md).
# IODD-2531
The IODD 2531 is a legacy 2.5-inch SATA virtual drive enclosure with ISO mounting, VHD/RMD/IMA support, multi-LUN operation, jog dial controls, and write-protection features. This reference page collects product specifications, menu behavior, usage notes, firmware links, and manuals for the IODD 2531.
## Appearance
   
## Functions
1. **Bootable Virtual CD-ROM, DVD-ROM, and Blu-ray Drive**
* Eliminates the need for physical optical drives and blank media for OS installations.
* Supports [ISO](https://en.wikipedia.org/wiki/ISO_image) images (CD, DVD, Blu-ray).
2. **Bootable Virtual USB and Flash Drive**
* Supports OS installation and multi-booting (including "Windows-To-Go").
* Operates as a [Virtual Disk Drive](https://en.wikipedia.org/wiki/Virtual_disk) with full USB flash drive functionality.
* Supports [VHD](https://docs.microsoft.com/en-us/windows-server/storage/disk-management/manage-virtual-hard-disks) and [VMDK](https://en.wikipedia.org/wiki/VMDK) (Virtual Hard Disk), RMD (Virtual Removable Disk), and [IMA](https://en.wikipedia.org/wiki/IMG_\(file_format\)) (Virtual Floppy Disk) formats.
3. **Multi-LUN Support**
* Simultaneously supports up to one optical drive, one physical hard drive, and four virtual drives.
4. **Hotkey for Safe Removal**
* Provides a dedicated hardware key for safe device disconnection.
5. **Write Protection**
* A logical and physical safeguard to protect data from unauthorized modification or virus infection.
* Includes an optional, hard-wired Write Blocker.
6. **Real-time AES 256-bit XTS Encryption (Note: Hardware Encryption is supported on iODD-2541)**
* Optional encryption using a 4-15 digit PIN (6 digits recommended).
7. **Loading State Retention**
* Automatically saves and restores the loading state and menu settings for subsequent boots.
### Menu
1. ***`Mode-Select`*** - Configure USB operation mode
1. *`Dual Mode`* - Concurrently mounts one physical disk and one virtual optical drive.
2. *`HDD Mode`* - Mounts the physical disk only.
3. *`CD Mode`* - Mounts the virtual optical drive only.
2. ***`Setting`*** - Device configuration
1. *`LCD Bright`* - Adjusts the LCD backlight brightness.
2. *`Idle Bright`* - Adjusts the LCD backlight brightness in power-saving mode.
3. *`Standby time`* - Configures the duration of inactivity before entering power-saving mode.
4. *`Load Default`* - Resets all settings to factory default values.
3. ***`Information`*** - System and drive information
1. *`S.M.A.R.T.`* - Displays internal drive health status.
1. *`HDD Temp`* - Current drive temperature.
2. *`HDD Health`* - Overall drive health rating.
2. *`HDD Model`* - Internal drive model name.
3. *`HDD Serial`* - Internal drive serial number.
4. *`Firmware Ver`* - Current device firmware version.
5. *`USB Speed`* - Current USB connection speed.
6. *`USB Input Volt`* - USB bus voltage (minimum and current).
4. ***`USB Connect`*** - Connection management
1. *`Refresh`* - Reconnects the device.
2. *`Safe Removal`* - Safely stops the internal drive and enters power-saving mode.
5. ***`Advanced`*** - Advanced features
1. *`Umount VHDD`* - Unmounts all active virtual disk drives.
2. *`Write Protect`* - Toggles write-protection for the drive.
* When a virtual drive is mounted, this setting applies to the virtual drive rather than the physical disk.
3. *`Instant Save`* - Manually saves current configuration.
4. *`Force USB 3.0`* - Enforces a USB 3.0 connection in environments with poor connectivity.
## Specifications
1. **External Interface**: USB 1.1 / 2.0 / 3.0 (up to 5 Gbps).
2. **Internal Interface**: SATA I / II / III (backward compatible).
3. **Drive Compatibility**: Supports 2.5-inch SATA HDDs and SSDs (up to 9.5mm height). Supports 4TB+ capacities.
* Note: While using virtual drive functions, the maximum partition size is limited to 2TB.
* 7mm drives require a spacer for proper installation.
4. **Controls**: 3-way jog dial, Back/Up button.
5. **Display**: 128 x 32 dot LCD.
6. **Materials**: Aluminum and Polycarbonate (PC).
7. **Architecture**: Successor to the ZM-VE300, sharing the same architecture with optimized hardware and ongoing firmware support.
## Usage Guide
Before using the device, please refer to the [Manual](#manuals) section.
### Basic Functions
#### Sample Folder Structure
Create a folder named `_ISO` in the root directory. The following folder tree is an example; any filenames or subfolders within `_ISO` are permitted.
```
J:
├─ _ISO
│ │ Hiren’s BootCD 15.2.iso
│ │ ubuntu-14.04.4-desktop-amd64.iso
│ │ Windows 10.iso
│ │ Windows XP sp3.iso
│ │ (Maximum of 32 files or subfolders per directory)
│ │
│ ├─ IMA for Floppy
│ │ Bios updater.ima
│ │ MS-DOS 6.0.ima
│ │ Symantec Ghost.ima
│ │
│ ├─ RMD for Setup
│ │ Win 7Ent_x86_x64+8.1Pro+10Pro vol2.RMD
│ │ Win7_Ult_SP1_Russian_x64.RMD
│ │ Windows 10.RMD
│ │
│ └─ VHD for Booting
│ │ linuxmint-17.3-cinnamon-32bit.vhd
│ │ Windows 10 Win2Go.vhd
│ │ Windows 7 OS Booting.vhd
│ │
│ └─ Nested subfolders are supported
├─ Your Folder 01
├─ Your Folder 02
├─ Your Folder 99
│ Your files 01.txt
│ Your files 02.txt
│ Your files 99.txt
```
#### 2531 Key Operations
1. **Navigation**
* `Jog Dial` Up/Down: Browse the file list.
* `Jog Dial` Click: Select a file.
* `Back/Up` Button: Move to the parent directory.
2. **Menu Access**
* Long press `Jog Dial` (3 seconds): Enter Menu mode.
* `Back/Up` Button: Exit Menu mode.
3. **Advanced Hotkeys (3-second press)**
* `Jog Dial` Up: Refresh the file list.
* `Jog Dial` Down: [Enter Power-Saving Mode](#power-saving-mode).
* `Jog Dial` Click: Enter Menu mode.
* `Back/Up` Button: Reboot device and detach all virtual drives.
4. **Startup Hotkeys (Hold while connecting)**
* `Jog Dial` Up: Start in **CD-MODE**.
* `Jog Dial` Down: Start in **HDD-MODE**.
* `Jog Dial` Click: Reset loading state and start in **DUAL-MODE**.
* `Back/Up` Button: Start in **Write-Protected** mode.
#### 2541 Key Operations
1. **Navigation**
* `2` / `8`: Browse up/down.
* `5` (or `6`): Select file (`6` maintains loading state on supported firmware).
2. **Menu Access**
* `Menu`: Enter or exit the Menu.
* `4`: Return to parent directory.
3. **Advanced Hotkeys (3-second press)**
* `1`: [Enter Power-Saving Mode](#power-saving-mode).
* `3`: Reboot device.
* `4`: Refresh file list.
* `7`: Reboot and detach all virtual drives.
* `0`: Reboot and temporarily disable Write-Protection.
4. No startup hotkeys are available for the 2541.
#### Power-Saving Mode
In power-saving mode, the drive's spindle motor stops and the LCD dims. The current virtual disk loading state is preserved.
* **2531**: Long press `Jog Dial` down (3 seconds).
* **2541**: Long press `1` (3 seconds).
#### File Selection and State Retention
To ensure that the selected file remains loaded after a reboot, the state must be saved.
* **2531**: Loading state is saved automatically on firmware 1558 or higher. For older versions, manual saving is required via [Power-Saving Mode](#power-saving-mode).
* **2541**: Using key `6` requires firmware 6(7)9-05 or higher to maintain the loading state.
#### Safely Removing the Hardware in OS
When the IODD partition is formatted as NTFS, it is mandatory to use the OS ejection feature before disconnection to prevent data corruption.
* Perform [Safely Remove Hardware](http://windows.microsoft.com/en-US/windows7/Safely-remove-devices-from-your-computer) before physical disconnection.
* If a write-protection error occurs during ejection, disable the Write-Protect setting and retry.
### Drive Initialization
The device supports two firmware types: NTFS and FAT32/exFAT. The NTFS version is installed by default.
1. Install the HDD or SSD into the IODD.
2. Connect the device to a PC.
3. Initialize the disk using the [MBR](https://en.wikipedia.org/wiki/Master_boot_record) partition style.
4. Format the primary partition as **NTFS** (for NTFS firmware) or **FAT32/exFAT** (for FAT firmware).
* Note: FAT32 has a 4GB file size limitation.
5. Create an `_ISO` folder in the root directory.
6. Copy ISO, VHD, RMD, or IMA files into the `_ISO` folder.
7. Perform a "Safely Remove Hardware" operation (mandatory for NTFS).
8. If the device is in power-saving mode, reconnect the USB cable. Otherwise, enter [Power-Saving Mode](#power-saving-mode) and then reconnect.
9. The LCD will display the device model followed by the filename of the selected image.
#### Full Hardware Reset
If initialization is unsuccessful, follow these steps:
1. Disconnect the USB cable.
2. Remove the drive from the IODD and connect it directly to a PC.
3. Initialize the disk as [GPT](https://en.wikipedia.org/wiki/GUID_Partition_Table).
4. Repeat the [Drive Initialization](#drive-initialization) process from the beginning (this forces a conversion from MBR → GPT → MBR).
5. **Follow these steps to perform a forced firmware update:**
1. Open the back cover.
2. Locate and hold the tact switch on the PCB.
3. Connect the USB cable.
4. Wait for approximately 7 seconds.
5. Release the tact switch.
6. Wait for approximately 1 minute for the process to complete.
### Troubleshooting (First Aid)
If the device malfunctions unexpectedly, try the following steps:
1. **2531**: Hold the `Jog Dial` while connecting the device to a PC.
2. Perform a "Safely Remove Hardware" operation in the OS.
3. Run a [Disk Check (CHKDSK)](https://en.wikipedia.org/wiki/CHKDSK) on the drive.
4. Rename the `_ISO` folder, create a new `_ISO` folder, and copy the files back into it (do not use "move").
5. Back up your data and perform a [Full Hardware Reset](#full-hardware-reset).
If hardware issues persist:
1. Restart your PC.
2. Replace the USB cable.
3. Connect the device to a motherboard USB port (rear panel).
4. Test the device on a different computer.
5. Replace the internal HDD/SSD.
### Virtual Optical Drive (ISO)
1. Copy ISO images to the `_ISO` folder.
2. Eject the device from the OS (mandatory for NTFS).
3. Enter [Power-Saving Mode](#power-saving-mode) or disconnect/reconnect.
4. Configure BIOS/UEFI to set the IODD or "USB CD-ROM" as the primary boot priority.
5. Select the desired ISO file from the device list.
6. If the computer fails to detect the boot device, restart the PC (Ctrl+Alt+Del).
#### Booting Errors
* Verify that the ISO image is bootable.
* If the PC does not support Multi-LUN, select **CD-MODE** or **ODD-MODE**.
* Test the ISO on a known-working system.
* If booting works with a real USB DVD drive but not the IODD, use a USB Y-cable for additional power.
* Disable or physically remove internal optical drives in the BIOS if conflicts occur.
* Ensure the OS being installed includes the necessary drivers for the target hardware platform (e.g., standard Windows 7 may lack drivers for Skylake platforms).
### Virtual Hard Disk (VHD)
* Only **fixed-size** VHD and VMDK files are supported. Dynamic VHD/VHDX formats are not compatible.
* Use [VHD Tool++](/product-reference-wiki/vhd-tool-plus-plus.md) to create unfragmented VHD files directly on the IODD.
* Renaming a `.VHD` file to `.VMDK` will allow it to be recognized as a VMDK disk.
* Upon selecting a VHD, the device may reboot and mount it as a standard USB disk.
* You can mount up to four virtual drives simultaneously by selecting files successively within 3 seconds.
1. Create a VHD file using the [VHD Tool++](/product-reference-wiki/vhd-tool-plus-plus.md).
2. Safely remove the device from the OS.
3. Enter [Power-Saving Mode](#power-saving-mode) and reconnect.
4. Select the VHD file from the device menu.
5. Configure the BIOS to boot from the mounted virtual drive.
### Virtual Removable Disk (RMD)
The process is identical to VHD usage, but the file extension must be changed to `.RMD`.
### Virtual Floppy Drive (IMA)
* Not supported on all hardware platforms.
* Supports uncompressed images: IMA, IMG, BIF, and VFD.
* Non-IMA extensions must be renamed to `.IMA`.
* Usage follows the same procedure as VHD/ISO mounting.
## Manuals
* [Iodd-2531 Quick Guide](https://dir.iodd.kr/Archive/iodd2531/manual)
* [Iodd Virtual Drive Guide](/product-reference-wiki/vhd-tool-plus-plus.md)
## System Messages
### Status Reference
1. **`"Please Wait"`** (Please Wait): Operation in progress.
2. **`"Plug Out ..."`** (Plug Out ...): Safe to disconnect the device.
3. **`"Data Saving..."`** (Data Saving...): Writing configuration changes to memory.
4. **`"Flash Update..."`** (Flash Update...): Firmware or font update in progress. **Do not disconnect the cable.**
### Error Codes
".." (..)
Navigation to the parent directory. This message indicates that the current folder contains no subfolders or supported file formats.
"ChkDsk (or gErr) : xxx" (ChkDsk (or gErr) : xxx)
Follow the [Troubleshooting (First Aid)](#troubleshooting-first-aid) steps.
"Check HDD" (Check HDD)
A disk error has occurred. Refer to the [Troubleshooting (First Aid)](#troubleshooting-first-aid) section.
"1st partition" or "unsupported partition" (1st partition or unsupported partition)
Firmware mismatch with the first partition's file system. Refer to the [Drive Initialization](#drive-initialization) section to align the partition type with the firmware version.
"bad or N/S HDD" (bad or N/S HDD)
Internal drive read failure. Check the HDD/SSD connection or replace the USB cable.
"Too Many Files" (Too Many Files)
Limit of 32 files/folders per directory reached. Organize files into subfolders.
"NO _ISO Folder" (NO _ISO Folder)
The required `_ISO` directory was not found. Create it in the root directory.
"NO - DISC" (NO - DISC)
No compatible files detected inside the `_ISO` folder.
"Disc Locked" (Disc Locked)
The virtual drive is locked by the OS or an application. Close accessing programs or reconnect the device.
"DEFRAG" (DEFRAG)
File fragmentation detected. ISO files support up to 24 fragments; VHD/RMD files must be unfragmented. Perform a [Disk Defragmentation](https://en.wikipedia.org/wiki/Disk_Defragmenter_\(Windows\)).
"vDISK Limit" (vDISK Limit)
Maximum limit of 4 concurrent virtual drives reached. Unmount an active drive to mount a new one.
"Already Hit" (Already Hit)
The selected file is already mounted.
"No Use Dynamic" (No Use Dynamic)
Dynamic VHD files are not supported. Use fixed-size VHDs.
"No Use Sparse" (No Use Sparse)
Sparse images are not supported.
### FAQ
The device does not boot.
Refer to the [Booting Errors](#booting-errors) section.
The LCD only displays "IODD 2531".
Refer to the [Troubleshooting (First Aid)](#troubleshooting-first-aid) section.
Mode automatically changes to CD-MODE when mounting a virtual drive.
This behavior is controlled by the filename properties. Refer to the [VHD Tool++](/product-reference-wiki/vhd-tool-plus-plus.md) documentation for naming conventions.
How to unmount virtual drives?
1. Press the side button for 3 seconds (Firmware 1555+).
2. Navigate to **Menu** -> **Advanced** -> **Umount VHDD**.
Firmware update fails repeatedly.
Refer to the [Firmware Update Instructions](#firmware-update-instructions).
## Firmware
### Update Instructions
**Requirements**: Windows PC and a high-quality USB cable. **Warning**: Connect only one IODD device during the update. The firmware version must match the file system of the first partition (NTFS or FAT/exFAT).
1. Download the appropriate firmware package.
2. Extract the ZIP file to a local folder (do not run from within the archive).
3. Execute the updater application as Administrator.
4. If the device is detected, click **Update**.
* If not detected:
* Try a different PC or USB port.
* Replace the USB cable.
* **2541**: Hold the internal tact switch for 1 second while connecting.
* **2531**: Hold the internal tact switch until the device is detected (approx. 5 seconds).
5. Upon successful completion, click **Exit** and reconnect the device.
### Downloads
* [Latest Firmware Directory](https://dir.iodd.kr/iodd_firmware_updater)