[BUG] False AVX Warning & Architecture Mismatch on Apple Silicon (M1)

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Environment:

Hardware: MacBook Pro M1 (2021, ARM64)

Claude Code Version: 2.1.17

OS: macOS

Description: Claude Code incorrectly flags a lack of AVX support on an M1 Mac, suggesting an Intel-based baseline build of Bun (bun-darwin-x64-baseline). This indicates that the tool or its bundled dependencies are running via Rosetta 2 or pulling x86_64 binaries instead of native arm64 ones.

Key Inconsistencies:

CPU Misidentification: Warns about missing AVX (an Intel instruction set) on Apple Silicon.

Version Mismatch: The warning points to a URL for Bun v1.3.5, while the system reports v2.1.17 as the current version.

Update Loop: Running claude update does not resolve the warning or the architecture detection error.

What Should Happen?

Claude Code should detect the arm64 architecture natively and use the corresponding Bun runtime without triggering Intel-specific AVX warnings.

Error Messages/Logs

warn: CPU lacks AVX support, strange crashes may occur. Reinstall      
  Bun or use *-baseline build:                                                                                                                
  https://github.com/oven-sh/bun/releases/download/bun-v1.3.5/bun-darwin-x64-baseline.zip                                                     
  Current version: 2.1.17

Steps to Reproduce

claude install

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.17

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Warp

Additional Information

_No response_