OpenTUI fails to start on Windows ARM64: bun:ffi dlopen() is not available in this build

Description

I'm unable to start the TUI on a Windows 11 ARM64 machine.

The CLI installs successfully via Winget and most commands work as expected, but any command that starts the terminal UI fails with the following error:

Failed to initialize OpenTUI render library: bun:ffi dlopen() is not available in this build (TinyCC is disabled)

Device: Microsoft Surface Laptop 7 Architecture: ARM64 OpenCode: 1.18.4 Installed via Winget (SST.opencode)

Interestingly:

• opencode --help ✅ works
• opencode --version ✅ works
• opencode web ✅ works
• opencode ❌ fails
• opencode --mini ❌ fails

This looks like the ARM64 build is unable to initialize the native OpenTUI renderer.

Additional information

opencode web works correctly, so the CLI itself is functional.

The issue only occurs when initializing the terminal UI (OpenTUI).

Output:

Error: Unexpected error

Failed to initialize OpenTUI render library:
bun:ffi dlopen() is not available in this build (TinyCC is disabled)

Plugins

None

OpenCode version

1.18.4

Steps to reproduce

1. Install OpenCode using Winget:

   winget install SST.opencode

2. Open PowerShell.

3. Verify installation:

   opencode --version

4. Run:

   opencode

5. The application immediately exits with:

   Failed to initialize OpenTUI render library:
   bun:ffi dlopen() is not available in this build (TinyCC is disabled)

Screenshot and/or share link

No response

Operating System

Windows 11 ARM64

Terminal

Windows PowerShell 7 (also reproducible in the VS Code integrated terminal)