NOW SpinRite 6.1 – Fast and useful for spinning and solid state mass storage!
Windows, Linux & Mac users can verify any PC compatible
computers' BIOS and FreeDOS boot compatibility.


This BootAble ZIP archive also contains a BootAble IMG file for non-Windows Linux & Mac users:
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To obtain direct, low-level access to a system's mass storage drives, SpinRite runs under a GRC-customized version of FreeDOS which has been modified to add compatibility with all file systems. In order to run SpinRite it must first be possible to boot FreeDOS.

This ZIP archive contains a BootAble Windows utility and also a BootAble file system image (bootable.img) to allow any Windows, Linux or Mac user to create BIOS-bootable media in order to workout and confirm the details of getting a machine to boot FreeDOS through a BIOS. Once the means of doing that has been determined, the media created by SpinRite can be booted and run in the same way.

Creating BootAble media
“Secure Boot” and Legacy / BIOS / CSM mode

Microsoft created “Secure Boot” specifically to prevent unsigned operating systems (like DOS or FreeDOS) from booting on modern computers, and Intel has replaced the original BIOS startup firmware (which all DOS's require) with UEFI.

In order to boot FreeDOS – which BootAble and SpinRite require – “Secure Boot” must be temporarily turned off (if it's on), and a system's startup firmware must have Legacy, BIOS, or CSM boot mode enabled. (Do not turn off secure boot until you check for BitLocker. See below.) Some systems refer to “CSM” which stands for Compatibility Support Module – another name for BIOS – so that's what you want.

Therefore, to boot FreeDOS and run BootAble or SpinRite: If “Secure Boot” is ON it needs to be turned off (but see the important details below, first!) and if a system has UEFI firmware its ability to also boot Legacy, BIOS, or CSM must be enabled.

Although booting different operating systems was once straightforward, as the need to do so has diminished, the knowledge required to do so has become less available. After inserting a bootable USB thumb drive, CD or diskette, it's usually necessary to press some key on the keyboard to interrupt the normal, default, internal drive boot process; but is it DEL, ESC, F2, F10 or F12? There's no standard key. It depends upon the machine because different manufacturers do it differently. And when exactly during the boot process should the key be pressed? It may also be necessary to temporarily change a boot setting or two because Windows systems may employ a system known as “Secure Boot” which prevents malware from infecting the Windows boot process. On top of all that, it's possible for the newest computers to no longer have the capability to boot a BIOS-based operating system at all. The next version of SpinRite, v7, will be able to boot on BIOS or UEFI, but all previous versions of SpinRite including v6.1, depend upon FreeDOS, which needs a BIOS.

This sounds more complicated than it is. Very few people are unable to get their machines to boot FreeDOS – but since that number is not zero, we provide these free “bootability” testing tools to allow users to experiment with working out the details of booting BIOS and FreeDOS on whatever machines they might want to use with SpinRite.

Because booting into DOS may be more involved than it once was, GRC's web forums have a “Booting DOS for SpinRite” forum dedicated to sharing solutions for booting PCs into DOS.

Accessing a machine's startup configuration

In order to inspect and possibly alter a system's boot settings it's necessary to interrupt the machine's normal boot process:

Secure boot and BitLocker
Disabling Windows' “Secure Boot” while BitLocker is in use and not
temporarily suspended will ERASE any BitLocker encryption keys.

Window's “Secure Boot” must be disabled in the system's startup configuration in order to boot other operating systems (including SpinRite's FreeDOS). But if Microsoft's BitLocker drive encryption is in use and has not been suspended (see “Suspending BitLocker” below) when Secure Boot mode is disabled, BitLocker's encryption key will be deliberately erased. This is done to protect the contents of encrypted drives from other operating systems. In this case, BitLocker's “Recovery Key” will be required once Secure Boot is re-enabled and the system is rebooted into Windows.

Backing up BitLocker recovery keys

Even though protection can and should be suspended (see the next section below) before disabling Secure Boot mode, which will protect BitLocker's keys from deletion while Secure Mode is disabled, BitLocker Recovery Key(s) should always be on hand whether or not you ever disable Secure Boot mode. Now would be a good time to back them up:

Suspending BitLocker protection

To prevent Windows from over-protectively deleting any BitLocker keys, BitLocker's protection may and should be temporarily suspended before Secure Boot mode is disabled. It can and should later be re-enabled once Secure Boot mode has been re-enabled:

Changing startup settings

Once Secure Boot mode has been safely disabled, Legacy or BIOS or CSM (Compatibility Support Module) mode can be enabled and you can see whether you're able to get BootAble to successfully boot.

This is what success looks like:
Getting help with booting

In addition to this page, a great deal of additional help, suggestions and guidance can be found online in GRC's terrific web forums. You do not need to create an account or login to read everything that's available there. The forums have a section dedicated to solving boot mysteries.

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Last Edit: Apr 23, 2024 at 13:18 (53.38 days ago)Viewed 176 times per day