GDIBuilder v1.3

This tool will assist in building .gdi images of a Dreamcast GD-ROM disc. It creates the track03.bin track (and final data track for images with CDDA) to be used in a .gdi. This tool cannot be used for MIL-CD's or tracks intended for a normal CD-ROM.

Download v1.3 for Windows - Windows 7 or newer

Download v1.3 for Mac - Mac OS X 10.11 or newer

Download v1.3 for Windows x64 (Command Line) - Windows 7 or newer

Technical Details
The primary executable on a Dreamcast GD-ROM (usually 1ST_READ.BIN) must be located at a specifc LBA sector for the disc to boot. According to dissassembly research done by japanese_cake, the required start location must be at least 100 minutes into the disc. This tool was created to make it easier to generate images with the executable in the correct location. On official media, when CDDA is used 150 empty sectors always separate the data and audio tracks on the disc. The tool also accounts for this when generating the data tracks. Finally, the IP.BIN bootsector contains a table of contents starting at offset 0x100. This TOC lists the tracks in the high-density area of the disc along with their LBA offset and track type. This information is written to the bootsector of the generated image.

Version History
Version 1.3 (released 2019-12-07) fixes empty folders being excluded from the build GD-ROM. It also sets the timestamps on folders to match the source folders added. On Windows, high DPI displays are now supported. On macOS, dark mode is supported and the application is notarized for macOS 10.15 and newer.

Version 1.2 added a feature to produce a truncated data track creating a gap in the disc. This allows for smaller GDI images to be created, however the resulting image is not technically valid and may be unsupported by some software or hardware. The option is disabled by default. In the UI it is enabled with a checkbox in the Advanced Options window; in the command line version adding the -truncate argument will enable this mode.

Source Code
The complete source code to the application is available on Github:

File timestamps change when I extract a GD-ROM and rebuild it?
There is a bug in the popular tool "GD-ROM Explorer" by japanese_cake, which ignores the time zone information on all disc timestamps. This will cause the timestamps on files to shift by how far your time zone is from UTC each time you rebuild a disc with the same files. I reported this bug to the original developer on November 2nd 2019, but after not hearing back for a month I fixed it myself. You can download the unofficial patched version of this program below.
Download Unofficial GD-ROM Explorer v1.6.3.2 for Windows - Not official, do not report any bugs to the original developer without confirming if they exist in an official release.

I have also ported this to macOS, because if it would be nice to be able to extract GD-ROMs on macOS if you can build them there. This is a very crude port developed in a few hours. It will work, but has some minor visual bugs. See the included Readme file for details.

Download Unofficial GD-ROM Explorer v1.6.3.2 for macOS - Not official, do not contact the original developer about this port.

Previous release(s)
Download v1.2 for Windows - Windows XP or newer

Download v1.2 for Mac - Mac OS X 10.7 or newer

Download v1.2 for Windows (Command Line) - Windows XP or newer; Compatible with Mono on Linux and OS X.