From 7b0748c86896ffd10ebe01d236b3f652a14d959e Mon Sep 17 00:00:00 2001
From: archipelago <archipelago@localhost>
Date: Mon, 29 Jun 2026 08:36:04 -0400
Subject: [PATCH] fix(mesh): respect the radio's flashed LoRa region (don't
 force ours)
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ensure_lora_region previously force-overrode the device's region with the
mesh-config region (EU_868) whenever they differed — which would shove a US/ANZ
user's radio onto EU_868: an illegal band that also cuts it off from its local
mesh. Off-the-shelf interop must respect whatever region the user flashed.

Now: a radio that already reports a REAL region (US, EU_868, ANZ, …) is left
untouched. We only set a region when the device reports UNSET (a fresh radio is
RF-silent and can't mesh at all), using the operator-configured region as the
fallback. Unknown/None (never reported) is also left alone. Pairs with the
default-channel change so a meshtastic archy node behaves like a stock device.

cargo check green (built into the same binary as the channel fix).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
---
 core/archipelago/src/mesh/meshtastic.rs | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/core/archipelago/src/mesh/meshtastic.rs b/core/archipelago/src/mesh/meshtastic.rs
index 29206870..d8127ede 100644
--- a/core/archipelago/src/mesh/meshtastic.rs
+++ b/core/archipelago/src/mesh/meshtastic.rs
@@ -296,11 +296,31 @@ impl MeshtasticDevice {
             return Ok(false);
         }
         match self.current_region {
-            Some(cur) if cur == code => Ok(false),
-            _ => {
+            // The radio already has a REAL region (US, EU_868, ANZ, …). RESPECT
+            // it — never override the region the user flashed/configured. Forcing
+            // our configured region onto, say, a US radio would put it on an
+            // illegal band and cut it off from its local mesh. Off-the-shelf
+            // devices keep whatever region they came with; `code` (the
+            // mesh-config region) is only the fallback for a fresh radio below.
+            Some(cur) if cur != REGION_UNSET => {
+                if cur != code {
+                    debug!(
+                        device_region = cur,
+                        configured_region = code,
+                        "Respecting the radio's own LoRa region (not overriding with the configured one)"
+                    );
+                }
+                Ok(false)
+            }
+            // Region is UNSET → a fresh radio is RF-silent and can't mesh at all.
+            // Set the operator-configured region so it can transmit/receive.
+            Some(_) => {
                 self.set_lora_region(code).await?;
                 Ok(true)
             }
+            // Region unknown (never reported in want_config) — don't guess /
+            // don't override; leave it for the user to set.
+            None => Ok(false),
         }
     }