WinBoat is an open-source command-line utility, developed in C#, designed to create reliable, bootable Windows USB drives, primarily optimized for UEFI systems. Its core purpose is to simplify the preparation of Windows installation media from ISO files, specifically addressing challenges with large Windows Image (WIM) files and file system limitations. It offers a robust alternative by focusing on a specific, effective strategy for UEFI compatibility.

WinBoat primarily solves the 4GB file size limit of the FAT32 file system. Modern Windows ISOs, especially Windows 10 and 11, often contain an `install.wim` file exceeding this. While FAT32 is preferred for broad UEFI boot compatibility, formatting an entire USB drive as FAT32 fails with large `install.wim` files. Conversely, an all-NTFS drive, though supporting large files, can cause boot issues on some UEFI systems. WinBoat circumvents this dilemma with a clever dual-partition strategy.

Upon execution, WinBoat intelligently partitions the target USB drive into two distinct volumes. A FAT32 partition holds essential UEFI boot files like `bootmgr`, `bootx64.efi`, and `boot.wim`. A second, larger NTFS partition stores all other Windows installation files from the ISO. Crucially, if `install.wim` exceeds 4GB, WinBoat automatically splits it into multiple `.swm` files (e.g., `install.swm`, `install2.swm`) and places these on the NTFS partition. To ensure the Windows installer can locate these, WinBoat modifies the `boot.wim` file on the FAT32 partition to correctly point to the `.swm` files on the NTFS volume. This intricate process ensures both UEFI bootability and successful handling of large installation images.

Beyond its innovative partitioning and WIM splitting, WinBoat leverages standard Windows utilities like `diskpart`, `wimlib-imagex`, and `bcdboot`, contributing to its reliability. It supports Windows 10 and 11 ISOs and requires the .NET 6.0 Runtime. Its command-line interface, while requiring terminal familiarity, offers precise control, making it suitable for scripting and automated deployments.

Compared to popular tools like Rufus or Ventoy, WinBoat carves a niche by specifically addressing the `install.wim` size issue, guaranteeing UEFI bootability without compromise. Rufus often forces a choice between FAT32 file size limits or NTFS boot compatibility problems. Ventoy, while excellent for multi-boot, can be overkill for a single, dedicated Windows installation drive. WinBoat offers a streamlined, reliable solution for users needing a robust, UEFI-compatible Windows installation USB, especially with large Windows ISOs.