Writing a single image

Not every job needs a multiboot drive. Since version 0.1.9, BootForge can also write one image directly to a drive, the way a desktop flashing tool would, and build dedicated Windows installer sticks. Both live alongside the multiboot flow and both are free.

Choosing a build mode

When you connect a blank or unrecognized drive, Home shows a chooser: set the drive up for multiboot, or write a single image to it. The single-image flow is also reachable from Tools, and from an image you already imported into your Library.

Writing an ISO

Pick the ISO, confirm the target drive, and BootForge writes it byte for byte, replacing everything on the drive.

Everything destructive sits behind the same confirmation used everywhere else in the app: the drive’s name and capacity, a plain erase warning, and a checkbox you must tick.

One guard worth knowing about: if the file you picked is stored on the target drive itself, BootForge refuses the write instead of destroying the source mid-copy.

ISOs built for older BIOS PCs only

Some ISOs carry a boot entry for legacy BIOS PCs and none for UEFI, which is how most modern PCs start. Tiny Core Linux is a current example. When BootForge can read that from the image, it says so as soon as you pick it: to boot it, turn off Secure Boot and switch the PC to Legacy/CSM boot in its BIOS/UEFI setup, if the PC offers that. The notice appears on the multiboot route too, because a Ventoy drive doesn’t change which firmware the image was built for.

It’s a notice, not a block: you can still write the image. And no notice doesn’t mean the image boots in UEFI mode. BootForge only warns when it has read the image’s boot entries to the end.

Verifying the write

Verify after writing is a toggle on the write screen. Leave it on and the app reads the whole drive back and compares it byte for byte, so a corrupted write shows up on your phone rather than at the PC’s boot screen. It roughly doubles the total time, which is why you can turn it off.

Three outcomes, and the app tells you which one you got:

• Read-back verified. The drive matches the image byte for byte.
• Written without read-back verification. You turned the check off.
• Read-back matched, but the drive wouldn’t confirm it. Some drives will neither commit their cache nor let the app read the flash directly, so the check may have read the drive’s own buffer instead of what was stored. BootForge says so plainly and tells you to boot-test the drive before you rely on it.

A write that can’t put every byte where it belongs now fails rather than finishing quietly.

Raw .img files

Raw disk images are accepted on the same path. Before writing one, the app shows a caveat card saying plainly that it can verify the write but not that the image will boot; that depends on the image itself and the device it was built for. If that’s understood, the write proceeds exactly like an ISO write.

Compressed raw images (.img.xz, .img.gz, .zip) are expanded as they’re written, so there’s no need to extract them first. A compressed image that doesn’t declare its expanded size can’t be checked against the drive’s capacity beforehand; if the drive runs out of room the write stops safely rather than leaving something half-written without telling you.

Windows ISOs route differently

Raw-writing a Windows ISO produces a stick that won’t boot. That’s a property of how Microsoft builds its ISOs, not of any app. So when BootForge recognizes a Windows installer image, it doesn’t offer a raw write. Instead it offers the two routes that work:

• Copy it to a multiboot drive, where Ventoy boots the ISO as-is. See Copying images to the drive.
• Build a dedicated installer drive: BootForge formats the drive the way Windows setup media is laid out (GPT with a FAT32 partition), copies the ISO’s contents, and splits the one file too large for FAT32 into parts Windows Setup understands. The result boots straight into Windows Setup on UEFI machines. Every file is verified on the drive before the app reports it done and safe to unplug.

The installer mode is UEFI-only, with no Legacy/CSM support. Any PC that meets Windows 11’s requirements is UEFI. For the full walkthrough including the download step, see Make a Windows 11 install USB from an Android phone.

Windows Setup options

Before an installer drive is written, the Windows screen offers two optional cards. Both are free, and both only change what BootForge writes to the drive. What Windows Setup does with it is up to Setup.

Edition. BootForge reads the editions listed inside your ISO’s install image, with their build numbers, without changing anything in it. Pick one and BootForge records it in an answer file on the drive, so Setup can skip its “Which Windows?” screen. Leave it on Ask during setup and Setup asks as usual.

Setup options. Switches written into that same answer file:

• Skip the Microsoft account — asks Setup to hide the online account and Wi-Fi steps so you can finish with a local account, and answers the privacy questions with everything off. Newer Windows builds keep closing the ways around the account screen, and if yours has, Setup asks for an account anyway.
• Skip automatic BitLocker encryption — asks Windows not to encrypt the PC’s own drive by itself while it installs. You can still turn encryption on yourself once Windows is running.
• Start Windows in your language — sets the language, keyboard and number formats from your phone. Windows can only use a language your ISO actually contains.

Each of these applies where your Windows build allows it. Setup reads the answer file or ignores it depending on the build inside your ISO, and BootForge can’t promise what a build it hasn’t seen will do. If you pick nothing, no answer file is written at all.

The answer file never names a disk. Choosing where Windows goes stays with you, in Setup.

After the write

A drive holding a single written image is not a Ventoy drive: there’s no menu at boot and no file-copy management, and Home will say so when you reconnect it.

Your phone may also start calling it an unsupported USB drive. That’s expected. The drive now carries the image’s own format, which phones can’t browse but PCs read normally.

To go back to multiboot or to plain storage, prepare or format the drive again — see Preparing a drive and Removing Ventoy.