Custom Boot Video on Startup Screen | Steam Big Picture

Custom Boot Video for Steam Big Picture is a project that allows you to replace the default startup video in Steam's Big Picture Mode with your selected custom animation.

• Easily replace the default boot video with a selected custom one
• Automatic detection of Steam installation path
• Backup of original files before patching
• Copy custom configuration (Steam.cfg) into Steam root
• Restart Steam automatically after patching (in future)

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Installation

1. Authorize on the website
   Visit https://startup.dejelnieks.lv and log in.
   Choose the custom boot video you want to appear when Big Picture Mode starts.

2. Download the patcher
   After logging in, click the Download button at the top left of the website.
   You will get a ZIP file containing main.exe and example files.

3. Prepare required files

   • modificated.js – custom JavaScript module containing the replacement for module 28744. Include "HERE" where your Steam user ID should be inserted.
   • userid – plain text file containing your Steam user ID.
   • Steam.cfg – configuration file to copy into Steam root.

4. Run the patcher
   Execute main.exe (or the provided .exe), which will:

   • Locate chunk~2dcc5aaf7.js inside the Steam installation.
   • Create a backup of the original file.
   • Replace "HERE" in modificated.js with your Steam user ID.
   • Patch module 28744 in chunk~2dcc5aaf7.js.
   • Copy Steam.cfg into the Steam root folder.
   • (Future) Restart Steam automatically after patching.

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Uninstalling

To undo the changes:

1. Restore the backup file chunk~2dcc5aaf7_old.js.
2. Remove Steam.cfg from Steam root.

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Versions

• Mar 5 2025 — Alpha
• Nov 4 2025 — Beta: exe (automatic Steam detection, backup, patching, and configuration).
• ? — Beta2: Steam auto-restart