probing issues with flashing

core/archipelago/src/api/rpc/mesh/status.rs

@@ -101,6 +101,21 @@ impl RpcHandler {
             detected.iter().any(|d| d == &path),
             "{path} is not a detected mesh-radio candidate port"
         );
+        // Refuse to probe while a firmware flash is in flight. Confirmed
+        // live 2026-07-23: esptool ("multiple access on port?") and
+        // rnodeconf (OSError Errno 71 Protocol error on an RTS ioctl) both
+        // failed with symptoms consistent with a second process holding the
+        // same serial fd — the flash subprocess runs for minutes outside
+        // our own async runtime, so nothing previously stopped a concurrent
+        // `mesh.probe-device` call (e.g. the hot-swap modal's own re-probe)
+        // from opening the identical port at the same time and corrupting
+        // both operations' handshakes.
+        if let Some(job) = self.flash_job.read().await.as_ref() {
+            anyhow::ensure!(
+                job.snapshot().await.done,
+                "A firmware flash is in progress — refusing to probe the serial port until it finishes"
+            );
+        }
         // Only hold the mesh_service lock long enough for the quick
         // active-path guard check — NEVER across the actual probe, which
         // can take 15-60s across its internal collision retries. Confirmed