OtterOS — Technician Multi-Boot USB Toolkit

Built with AI-assisted development using Claude Code

Overview

OtterOS transforms a 256GB USB drive into a complete PC technician toolkit. It was built for daily use at a real computer repair shop in Israel and covers the full workflow — from booting on a bare machine to a fully configured, clean Windows installation with drivers and software installed.

The project is deployed by running a PowerShell script that syncs the repository to the USB drive. No build system, no complexity — just a working tool.

What It Does

Phase	Capability
Boot	Custom GRUB2 menu with organized categories: Windows ISOs, Recovery environments, Linux distros, Diagnostic tools
Install	Semi-unattended Windows setup — auto-skips EULA, Microsoft account, WiFi, privacy screens, Cortana
Configure	Post-install PowerShell toolkit: bloatware removal, telemetry disabling, performance tweaks, software installation
Diagnose	Portable diagnostic tools for CPU, GPU, storage, memory stress testing and health monitoring

Tech Stack

Boot Manager: Ventoy — boots multiple ISOs from a single USB without reformatting
UI: Custom GRUB2 dark theme with otter mascot branding
Automation: PowerShell scripts (post-install toolkit), XML (Windows unattended setup), Batch (launcher)
Deployment: setup.ps1 copies from GitHub repo to USB — source of truth lives in version control

Windows Installation

The autounattend.xml handles a three-pass unattended setup (windowsPE → specialize → oobeSystem):

Multi-language support — a single XML works for English, Hebrew, and Russian without swapping files; technician selects language at boot
Automatic local account — creates a “User” account with no password, bypasses Microsoft account requirement
Israel Standard Time set automatically
Microsoft account servers blocked via hosts file modification
Windows 11 bypass — TPM, RAM, and Secure Boot checks skipped for compatibility with older hardware

Post-Install Toolkit

After Windows boots, _LAUNCH.bat auto-detects the USB drive letter and opens a PowerShell menu:

Bloatware Removal Xbox apps, Teams, Candy Crush, TikTok, Spotify, Clipchamp, OneDrive

Telemetry & Privacy DiagTrack service disabled, activity history cleared, advertising ID removed

Performance High Performance power plan, registry tweaks for responsiveness

Software Installation (via winget) Chrome, 7-Zip, VLC, Notepad++, Discord, Steam

Driver Management SDIO (Snappy Driver Installer) with 65 driver packs (~55GB), plus standalone GPU/chipset drivers with guided installation order

Diagnostic Tools Included

Category	Tools
System Info	CPU-Z, GPU-Z, HWInfo
Disk Health	CrystalDiskInfo, CrystalDiskMark, Victoria
Stress Testing	FurMark, OCCT
Driver Management	DDU (Display Driver Uninstaller)
Memory	Memtest86

Bootable Environments

Windows 10/11 — English, Hebrew, Russian
Recovery — Sergei Strelec WinPE, Hiren’s BootCD PE, Rescuezilla
Linux — Ubuntu, Kali, GParted, SystemRescue
Diagnostics — Memtest86, HDAT2

Project Structure

OtterOS/
├── ventoy/
│   ├── ventoy.json        — Boot menu config, Win11 bypass flags
│   └── theme/             — Custom GRUB2 dark theme
├── Toolkit/
│   ├── Scripts/           — PowerShell post-install menu
│   ├── Drivers/           — Driver packs and installers
│   └── Tools/             — Portable diagnostic utilities
├── autounattend.xml       — Unattended Windows setup config
└── setup.ps1              — USB deployment script

Design Notes

Why Ventoy? Most multi-boot USB tools require reformatting to add new ISOs. Ventoy treats the drive as a regular storage device — drop in an ISO file and it’s bootable immediately. New Windows versions or recovery tools are added in seconds.

GRUB2 percentage constraint: All theme element positions must use whole-number percentages — decimal values silently crash the boot menu. The custom theme was built with this constraint in mind.

Self-detecting launcher: _LAUNCH.bat uses %~d0 to resolve its own drive letter at runtime, so the toolkit works regardless of which drive letter Windows assigns to the USB.