Posted on February 21, 2018 · Posted in Windows 10, Windows 7

Removable USB Flash Drive as Local HDD in Windows 10 / 7

In this article, we’ll show you how to make a USB flash drive or an SD card to be identified in the Windows as a common local hard disk. You, probably, may ask why it is necessary. The matter is that by default Windows identifies all the USB flash drives and SD cards as removable drives that can’t be split into several partitions with the built-in Windows tools. And even if you partition the USB flash drive into two or more volumes using third-party utilities (say, in Linux), only the first partition is available in Windows. Windows supports multiple partitions only for hard disk drives identified as local (i.e. non-removable).

RMB bit and USB drives

Windows recognizes an USB flash drives as removable devices due to the presence of a special descriptor bit RMB (removable media bit) on each of the devices. If the system determines that RMB=1 when polling the connected device using StorageDeviceProperty function, it concludes that this device is a removable drive. Thus, in order to convert the USB-flash to the hard disk it is enough to modify this descriptor.  You can do this directly (which is quite risky because of the differences in the device-specific hardware implementations, and not always possible), or indirectly, by replacing the response of a USB device using a special driver, which allows to filter out the information in the device response.

Tip. Some manufacturers release special utilities for flashing the controller of USB drives. First of all, try to find such utility and / or firmware on the manufacturer’s website. This is the most correct way. If this utility does not exist, follow the recommendations in this article.

Connect the USB flash drive to any available port on the computer, then open the Disk Management console (diskmgmt.msc) and make sure that it is determined by the system as Removable.

removable usb flash drive in windows disk manager console

Also you can view the type of device in the Volumes tab in the properties of the drive (as we see here Type: Removable).

removable disk

Or using the diskpart command:

list volume

diskpart check removable drive

In this article, we’ll look at two ways to change the RMB bit on a USB stick: using the Hitachi filter driver (changes are made only at a specific computer on the driver level) and changing the removable bit in the controller firmware using the BootIt utility from Lexar (more universal way, but there is a number of restrictions and is not applicable to all models of USB flash drives and SD cards). Although both of these methods are quite old and I originally tested them in Windows 7, they continue to be relevant and work equally well in modern Windows 10.

Lexar BootIt Utility: Flip Removable Bit

Recently I got a pretty interesting tool – Lexar BootIt. This is a free portable program that can change the RMB of a removable drive and making a removable USB device fixed (or vice versa). Despite the fact that the utility Lexar BootIt is developed only for Lexar devices (Micron, Crucial), it can work with flash drives from other manufacturers. The BootIt utility supports all versions of Windows, starting with Windows XP and ending with Windows 10.

Important. The utility is guaranteed to work with Lexar flash drives. Judging by the reviews, the “Flip removable bit” function does not work on fast USB 3.0 flash drives. In addition, when flashing the controller, you can lose the warranty on the USB flash drive and can make it unworkable.

You can download BootIt from Lexar website

  • Run exe elevated
  • In the list of devices, select your USB flash
  • Press the button Flip Removable Bit
  • Save changes by clicking OK.

lexar bootit flip removable bit

Unplug and reconnect the device. Using Device Manager, make sure that its type has changed from Removable to Basic.

usb flash as basic volume

In the event that the BootIt utility did not help to change the RMB bit on a removable drive, try the following method based on the Hitachi Microdrive filter driver.

Hitachi Microdrive Filter Driver for USB Flash Drives

To make a USB flash drive or an SD card to be recognized as a hard drive, you need a special filter driver, which allows you to modify data sent via the system stack of the current device driver. We will use a filter driver for USB flash drives by Hitachi (Hitachi Microdrive driver), which allows to change the USB device type from removable to fixed (USB-ZIP -> USB-HDD) at the OS driver level. Using this driver, you can hide from the system that the connected device is removable. As a result, the system assumes that it works with a usual hard disk, which can be split into several partitions available in the system simultaneously.

Hitachi Microdrive Driver Files:

You need to download the version of the driver in accordance with the bitness of your system. Both archives have identical structure and consist of two files:

  • cfadisk.inf – is the installation file with driver settings
  • cfadisk.sys – is a Hitachi driver file

The next step is to identify the device ID of your USB / SD flash drive. To do it open Device Manager and select the properties of your USB drive. On Details tab in the Device Instance Path setting, select and copy (Ctrl + C) the code for the device instance.

identify device id

In our example this would be:


Suppose we are going to install a driver on the 64-bit system.  To edit it, open cfadisk.inf in any text editor. We need the sections cfadisk_device and cfadisk_device.NTamd64.

%Microdrive_devdesc% = cfadisk_install,IDE\DiskTS64GCF400______________________________20101008
%Microdrive_devdesc% = cfadisk_install,IDE\DiskTS64GCF400______________________________20101008

Change the value DiskTS64GCF400______________________________20101008 with the ID of your device.

Important! In the code of the device instance, the part after the second “\” should be deleted (we delete 9876543210ABCDEF&0 in our example).

We get:

%Microdrive_devdesc% = cfadisk_install,IDE\USBSTOR\Disk&Ven_Linux&Prod_File-CD_Gadget&Rev_0000
%Microdrive_devdesc% = cfadisk_install,IDE\USBSTOR\Disk&Ven_Linux&Prod_File-CD_Gadget&Rev_0000

Save the file.

If the driver is installed on a 32-bit system, you have to download the corresponding archive, unzip it and open cfadisk.inf for editing. Find the section [cfadisk_device]:

%Microdrive_devdesc% = cfadisk_install,USBSTOR\Disk&Ven_LEXAR&Prod_JD_LIGHTNING_II&Rev_1100
%Microdrive_devdesc% = cfadisk_install,USBSTOR\Disk&Ven_JetFlash&Prod_TS1GJF110&Rev_0.00
%Microdrive_devdesc% = cfadisk_install,USBSTOR\DISK&VEN_&PROD_USB_DISK_2.0&REV_P

Then change the data in the last line, having specified the instance ID of our flash drive, i.e. in our example, we get:

%Microdrive_devdesc% = cfadisk_install,USBSTOR\Disk&Ven_LEXAR&Prod_JD_LIGHTNING_II&Rev_1100
%Microdrive_devdesc% = cfadisk_install,USBSTOR\Disk&Ven_JetFlash&Prod_TS1GJF110&Rev_0.00
%Microdrive_devdesc% = cfadisk_install,USBSTOR\Disk&Ven_Linux&Prod_File-CD_Gadget&Rev_0000


Tip. If you want a USB flash drive in the Device Manager to be displayed under a specific name, you have to edit Microdrive_devdesc variable, like this:

Microdrive_devdesc = "Trascend 64 GB DIY SSD"

Installing Hitachi Microdrive Driver Instead of the Native USB Flash Driver

You only have to replace the driver used by the USB flash drive.

Important! If Hitachi Microdrive USB driver is installed on a 64-bit system, since this driver is not digitally signed, you will have to disable driver signature verification on your system or to sign the driver yourself.

Open the Drivers tab and click Update Driver.

update device driver

Specify the path to the directory to which you have extracted the archive with Hitachi driver you had downloaded earlier.

browse path to hitachi microdrive driver

Select the new new driver

Ignore the warning of the missing digital signature of the driver.

ignore driver virify warning

Tip. In Windows 10 and Windows 8, when installing Hitachi Microdrive USB driver, this error occurs:

Windows found driver software for you device but encountered an error while attempting to install it
Hitachi Microdrive
The third-party INF does not contain digital signature information

Hitachi Microdrive inf not contain digital signature

To disable the digital signature verification of drivers, run the following commands:

bcdedit.exe /set nointegritychecks ON
bcdedit.exe /set TESTSIGNING ON

Restart the computer and try installing the driver again.

Now you only have to restart the computer and having opened the Disk Manager, verify that the flash drive is identified as a common hard disk (Type: Basic) and uses Hitachi driver.

usb flash drive as basic disk

By opening Windows Explorer, you can also make sure that the icon of the flash drive has changed: it is displayed as a common hard drive.

usb flash as local disk in windows

Now this flash drive can be used as a regular HDD: you can create partitions, specify the active partition, create dynamic disks, install software that does not work from USB flash drives, etc.

Important. It should be understood that this solution only works on the system on which the corresponding driver is installed. Without this driver, the second partition of the device will not be available on other Windows computers

How to Remove Hitachi Microdrive Driver

To delete Hitachi Microdrive driver, open the properties of the drive and click Update Driver on the Drivers tab. The system will install the native driver.

delete Hitachi Microdrive Driver

Tip. If, after installing the Hitachi driver, the system stops booting with the BSOD, you must boot your computer from the Windows installation media (or LiveCD) and manually delete the following files:

  • cfadisk.sys in the folder %windir%\System32\drivers
  • Folder «cfadisk.inf_amd64_…» in %windir%\System32\DriverStore\FileRepositoty

Restart the computer

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