How to create a bootable USB flash drive
This is a quick way to create a bootable USB flash drive with FreeDOS on it. This is usually done for the purpose of running native DOS software that can not run under Windows (such as BIOS flashing utilities). This procedure has been verified using Windows 7 Enterprise, 64 bit. With some luck, it will Just Work™ for you. If not, read the troubleshooting section.
Creating the bootable flash drive
- Download FlashBootKit.zip (113K)
- Unzip
- Right click your flash drive in Explorer and select Format
- In the Format Removable Disk dialog, select
- File system: FAT32
- Allocation unit size: 4096 bytes
- Volume label: <anything you like>
- Quick format: Check
- Copy the contents of the root folder in the unzipped kit over to the root of your flash drive
- Open a command prompt with administrative privileges
- Click Start
- In the search field, type cmd and Press Ctrl+Shift+Enter
- Click Yes in the User Access Control dialog if one appears
- Verify that the command prompt window title says "Administrator" in it.
- CD to the unzipped kit folder
- Type
syslinux -ma X:
Where X is the drive letter of your flash drive. Triple check the drive letter!
- Copy the files you need to access from DOS onto the flash drive, such as a BIOS flashing utility and a BIOS image file
- Reboot your computer, enter your boot menu and select your flash drive (it may be listed under hard disks)
Troubleshooting
Trouble while creating the bootable flash drive
Error message while running the syslinux -ma X: command
The syslinux command prints no messages if it runs successfully.
Error message:
Accessing physical drive: Access is denied. Did not successfully update the MBR; continuing...
You need an Administrator command line window even if you are a member of the administrator group. Make sure you hit Ctrl+Shift+Enter instead of just Enter after typing cmd.
Error message:
'syslinux' is not recognized as an internal or external command, operable program or batch file.
Did you CD to the correct directory? If you type
dir
You should see something like
Directory of D:\FlashBootKit
2009-12-06 16:03 <DIR> .
2009-12-06 16:03 <DIR> ..
2009-12-06 13:57 <DIR> root
2009-10-05 15:08 28,160 syslinux.exe
1 File(s) 28,160 bytes
3 Dir(s) 101,573,984,256 bytes free
Trouble booting from the flash drive
On my computer (NVIDIA 680i SLI with AWARD BIOS), hitting ESC repeatedly during POST brings up the boot menu.
Selecting the flash drive in a boot menu after rebooting is the best way to make sure that your flash drive is tried before any other devices during boot. But many computers (especially older computers) do not have a boot selection menu. In that case, you need to modify the boot order in your BIOS configuration to make sure that the flash drive is tried before any other bootable devices in your computer.
The flash drive is ignored and Windows boots instead of the flash drive
There are a few basic possible causes:
- The computer doesn't search the flash drive during POST
- The computer does search the flash drive during POST but doesn't find a boot sector
- The computer searches the flash drive, finds a boot sector and runs it but the boot sector can't start the OS
Booting from a flash drive requires support in your computer's BIOS. BIOS support for flash drives has gone through several stages. At first, flash drives were supported through various emulation modes like USB floppy drive, USB CD-ROM drive and hard drive emulation. Preparing a flash drive for use for the different emulation modes requires different procedures. A flash drive prepared according to this guide should work with "no emulation" and "hard drive emulation" modes. If your BIOS doesn't support these modes, you will need to search online for alternative procedures.
You may see settings like USB-FDD, USB-ZIP, USB-CDROM and USB-HDD in your computer's BIOS configuration. A flash drive prepared according to this guide should work with the USB-HDD setting.
Did you copy the contents of the root folder into the root of the flash drive? If you open the flash drive in Windows, you should not see a folder named "root" in the root of the flash drive.
A single flash in the LED on the flash drive flash during POST could indicate that your computer at least searches the flash drive.
To speed up testing of different BIOS configurations, remove your Windows drive from the boot options.
Some combinations of flash drives and motherboards do not work. Try another flash drive and/or another computer.
Some motherboards, for instance FIC AU13 with AWARD BIOS, require USB Legacy Support to be turned on in the BIOS configuration.
Versions
The version of FreeDOS in FlashBootKit is 1.0 Final.
The version of SYSLINUX in FlashBootKit is 3.83.
