From 9f546d7fddadbff6ba921940802caa21700d5b2a Mon Sep 17 00:00:00 2001
From: Will Greenberg <willg@eff.org>
Date: Tue, 21 Jan 2025 15:00:13 -0800
Subject: [PATCH] serial: fix UTF-8 panic on macOS

---
 serial/src/main.rs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/serial/src/main.rs b/serial/src/main.rs
index 02f32b3..05b53c7 100644
--- a/serial/src/main.rs
+++ b/serial/src/main.rs
@@ -78,7 +78,10 @@ fn send_command<T: UsbContext>(handle: &mut DeviceHandle<T>, command: &str) {
         .read_bulk(0x82, &mut response, timeout)
         .expect("Failed to read response");
 
-    let responsestr = str::from_utf8(&response).expect("Failed to parse response");
+    // For some reason, on macOS the response buffer gets filled with garbage data that's
+    // rarely valid UTF-8. Luckily we only care about the first couple bytes, so just drop
+    // the garbage with `from_utf8_lossy` and look for our expected success string.
+    let responsestr = String::from_utf8_lossy(&response);
     if !responsestr.contains("\r\nOK\r\n") {
         println!("Received unexpected response{0}", responsestr);
         std::process::exit(1);