Browser Installer¶
PAI's browser installer at pai.direct/flash-web lets you download, verify, and prepare a PAI USB drive without installing any tools first.
What it does¶
- Detects your OS — Windows, macOS, or Linux — and checks browser capabilities.
- Downloads the PAI ISO directly to your machine with real-time progress.
- Verifies SHA256 in-browser using a streaming hash (no buffering the entire file).
- Generates a one-liner precisely tailored to your OS and the verified ISO path.
- Offers copy-and-run — paste the command in your terminal and the ISO is flashed.
What it does NOT do¶
- It does not write directly to USB in most cases. Browsers cannot access block devices via standard APIs.
- It does not collect any telemetry, analytics, or error logs. Everything runs locally.
- The ISO is downloaded directly from GitHub Releases to your browser — PAI's servers never see the file.
WebUSB write (experimental)¶
On Chromium-based browsers (Chrome, Edge, Brave), an experimental "In-Browser WebUSB Write" option is available. This attempts to write the ISO directly to a USB drive using the WebUSB API.
OS compatibility¶
| OS | WebUSB Write Status |
|---|---|
| Linux | Most likely to work. The OS is more permissive about releasing USB devices. |
| Windows | Requires the USB drive to be unmounted/ejected first. May fail if Windows holds the driver. |
| macOS | Hit-and-miss. macOS aggressively claims mass-storage devices. |
Requirements¶
- Chromium-based browser (Chrome, Edge, Brave, Opera)
- User must explicitly opt in via an "I understand this is experimental" checkbox
- The USB device must not be in use by the OS
If WebUSB fails at any step, the installer falls back to the Quick (copy-paste) method.
Privacy¶
- No telemetry. The page does not log visits, funnel steps, or errors to any server.
- No CDN calls. All JavaScript and CSS is bundled. The only network request at runtime is the ISO download from GitHub.
- Offline-capable. Once loaded, the page is cached by a service worker so you can use it even if your connection drops mid-flow.
Browser support¶
| Browser | Quick (copy-paste) | WebUSB Write |
|---|---|---|
| Chrome / Edge (last 2 versions) | ✅ | ✅ (experimental) |
| Firefox (last 2 versions) | ✅ | ❌ (API not available) |
| Safari (last 2 versions) | ✅ | ❌ (API not available) |
Troubleshooting¶
"SHA256 support: Not available"¶
Your browser does not support Web Workers. Update to a modern browser (Chrome, Firefox, Safari, or Edge released in the last 2 years).
"Streaming downloads: Not supported"¶
Your browser does not support the Streams API. This is required for downloading large files without buffering. Update your browser.
Download blocked by corporate proxy¶
If your network blocks downloads from github.com, download the ISO manually from the Releases page and use flash.sh --local-iso or flash.ps1 -LocalIso directly.
File System Access API unsupported¶
On Firefox and Safari, the page falls back to a standard <a download> trigger. The file will be saved to your default Downloads folder. You may need to confirm the download in your browser.
WebUSB: "Your OS is holding the USB driver"¶
Close any File Explorer, Finder, or file manager window that shows the USB drive. On Windows, right-click the drive in Explorer and choose "Eject." On Linux, run sudo umount /dev/sdX* first. Then retry.
WebUSB: no bulk OUT endpoint found¶
The selected device may not be a standard USB mass storage device, or its interface descriptors are non-standard. Use the Quick (copy-paste) method instead.