Project Stellar - Firmware Update 1.2.0

Project Stellar - Firmware Update 1.2.0

Hello everyone! Here we are, surfing through the space-time continuum, and we've just realized something amusing – we've been so engrossed in the development of Project Stellar that we completely spaced out on discussing a major milestone: the firmware update 1.2.0.

Better late than never, right? For those who missed it, this update actually made its grand entrance back in August. Now, let's rewind a bit and dive into what this belatedly celebrated update brings to the table.

Before we delve in, it's worth noting that this post serves mostly as a historical record. We're on the cusp of rolling out the next big thing – firmware update 1.3.0 – which is right around the corner. But before we leap into the future, let's take a moment to appreciate the journey thus far and the strides made with 1.2.0. Stay tuned, as the best is yet to come!

(X)ISO and Compressed ISO Support

Revolutionizing Game Installation

In the past, installing games on the Xbox required copying the contents of the game disc to the hard drive, followed by patching the game executable to circumvent the Xbox's file system limitations. This method was far from ideal.

Enter Project Stellar, where we're shaking up these old practices. Our update 1.2.0 is a testament to our commitment to making patching obsolete.

Furthermore, extracting games to the hard drive in the traditional manner has several drawbacks:

  1. Increased Storage Space Usage: Games with numerous files can occupy significantly more space due to drive cluster sizes, potentially leading to gigabytes of wasted storage.
  2. Risks of Copy and Patch Errors: The possibility of files not being copied or patched correctly can introduce game errors and inconsistencies.
  3. Heightened Risk of Disk Fragmentation: The increased number of files and frequent write operations heighten the risk of disk fragmentation, which can negatively impact both performance and the longevity of the hard drive.

Different Formats for Different Folks

Stellar 1.2.0 implements support for all kinds of different formatted ISO images.

  1. The Classic ISO: This format is a 1:1 copy of a game disc, similar to a Redump image, minus the video partition. It occupies 7.4GB per game, which is quite sizable. Ideal for those who want an exact backup, it's less suited for users with limited storage space.

  2. XISO - The Preferred Choice:
    XISO repacks the original ISO by removing non-essential padding, a legacy of optimizing games for physical disc loading. This procedure greatly reduces the file size, maintaining the game's integrity and functionality.

    The primary advantage of XISO files is their storage efficiency, featuring significantly smaller file sizes and faster load times, without compromising the original game's integrity.

    We recommend this format for most Project Stellar users, as it offers a great balance between storage efficiency, performance, and compatibility.

  3. CISO - Compact but Slower: The compressed ISO, or CISO, uses LZ4 compression to reduce file sizes at the cost of slightly longer loading times. It's a good option for those prioritizing maximum storage utilization over performance.

Lessons Learned 

As we've navigated the development of Project Stellar, we've come to understand some crucial aspects of game compatibility and the role of image formats.

In the early stages, our strategy was centered around untouched compressed ISOs. We thought this was the key to achieving perfect game compatibility. What became clear, however, was that existing modifications fell short in this regard, particularly when it came to repacked images. The reality was that with the conventional mods, achieving flawless compatibility with repacked images was a challenge that hadn't been effectively addressed.

This is where Project Stellar marks a significant departure from the norm.

Our method involves complete emulation of the disc drive, a crucial step that allows us to eliminate the need for disc padding. While this might lead to less impressive compression figures compared to repacked ISOs, it opens up an entirely new realm of possibilities: we can now support repacked ISOs with full compatibility. And this is something quite unprecedented.

With Project Stellar, we're not just adapting existing methods for loading ISO images; we're fundamentally redefining them, setting new standards for game compatibility and storage efficiency.

Open Source Contributions

Alongside the 1.2.0 update, we're also proud to release two new open-source projects.

These open-source projects reflect our dedication to community-driven development and innovation in gaming technology. Stay tuned for more updates from Project Stellar!

This Xbox executable is a key component of Project Stellar. It's designed for mounting and launching disc images, streamlining the process of playing your favorite games.

Complementing our storage solutions, this utility allows users to efficiently compress their game discs into the CISO format. It's an essential tool for those looking to save space without compromising on game quality.

Open source software is very important to us here and contributing back is one of the many ways we like to show our support.




  • Added support for virtual ISOs, XISOs, and compressed ISOs (CSO).
  • Added Extended Retail PFN support for RAM upgraded systems.
  • Automatically disable extended RAM during safe mode.
  • Changed default IGR button combo to LT+RT+BACK+BLACK.
  • Added IGR button combo settings.
  • Fixed hard drives being left disabled on generic system errors.
  • Fixed USB IRQ memory corruption issue.
  • Fixed Stellar memory cache bug.
  • Fixed FTP corruption issue.
  • Fixed system restarting on DVD eject for NONSECURE_MODE titles (DVD2Xbox).
  • Stability and performance improvements.


  • Fixed drive addressing issue on some IDE/SATA drives.
  • Fixed HDD tool attempting to format partition F on drives too small.
  • Improved TCP/IP fragmentation.


  • Added Diagnostic screen
  • Store and display partition mount status, including error code, on Driver Overview. 


  • Added Diagnostic screen
  • Store and display partition mount status, including error code, on Driver Overview.


As we wrap up this update on Project Stellar, it's clear that we're on a journey of continuous innovation and improvement.

From expanding our support for diverse ISO formats to breaking new ground with our open-source initiatives and redefining game compatibility standards, we are committed to enhancing your gaming experience in ways previously unimagined. The lessons we've learned and the advancements we've made with Project Stellar are just the beginning.

We're excited to keep pushing boundaries and exploring new possibilities. Stay tuned for more updates as we continue to evolve Project Stellar, and thank you for joining us on this remarkable adventure into the future of retro.