zeroclaw-labs/zeroclaw · error

Built binary not found at {}

Error message

Built binary not found at {}

What it means

After a successful cargo build, flash_nucleo_firmware expects the ELF at firmware/nucleo/target/thumbv7em-none-eabihf/release/nucleo. This bail fires when cargo reported success but the artifact is not at that hardcoded path — build output was redirected elsewhere or the binary has a different name.

Source

Thrown at crates/zeroclaw-hardware/src/peripherals/nucleo_flash.rs:60

    let build = Command::new("cargo")
        .args(["build", "--release", "--target", TARGET])
        .current_dir(&firmware_dir)
        .output()
        .context("cargo build failed")?;

    if !build.status.success() {
        let stderr = String::from_utf8_lossy(&build.stderr);
        anyhow::bail!("Build failed:\n{}", stderr);
    }

    let elf_path = firmware_dir
        .join("target")
        .join(TARGET)
        .join("release")
        .join("nucleo");

    if !elf_path.exists() {
        anyhow::bail!(
            "Built binary not found at {}",
            elf_path.display().to_string()
        );
    }

    println!("Flashing to Nucleo-F401RE (connect via USB)...");
    let flash = Command::new("probe-rs")
        .args([
            "run",
            "--chip",
            CHIP,
            elf_path.to_str().context("ELF path is not valid UTF-8")?,
        ])
        .output()
        .context("probe-rs run failed")?;

    if !flash.status.success() {
        let stderr = String::from_utf8_lossy(&flash.stderr);

View on GitHub (pinned to 88bb9c8533)

Solutions

1. Unset CARGO_TARGET_DIR and remove/adjust build.target-dir overrides, then rebuild
2. Locate the real artifact: `find firmware/nucleo -name nucleo -type f` and align the target dir with the expected path
3. Ensure firmware/nucleo produces a binary named `nucleo` (package name or [[bin]] name = "nucleo")

Example fix

# before
export CARGO_TARGET_DIR=/shared/target
# flash reports: Built binary not found at .../firmware/nucleo/target/thumbv7em-none-eabihf/release/nucleo

# after
unset CARGO_TARGET_DIR
# rerun the Nucleo flash

if std::env::var_os("CARGO_TARGET_DIR").is_some() {
    anyhow::bail!("CARGO_TARGET_DIR set: artifacts will not land where the flasher looks");
}
flash_nucleo_firmware()?;

When it happens

Trigger: CARGO_TARGET_DIR is set (or build.target-dir is set in .cargo/config.toml) so cargo writes artifacts to another location; the firmware package's binary is renamed via [[bin]] so no file named `nucleo` is produced.

Common situations: Shared CARGO_TARGET_DIR in CI or shell profiles; repo-wide .cargo/config.toml redirecting output for caching; refactors of firmware/nucleo that change the package or bin name.

Related errors

• Build failed:\n{}
• probe-rs not found. Install it: cargo install probe-rs-too
• Nucleo firmware not found at {}. Run from zeroclaw repo root

AI-assisted analysis of zeroclaw-labs/zeroclaw@88bb9c8533 (2026-08-23). Data as JSON: /api/errors/06a0ca085504d3df. Report an issue: GitHub.