diff --git a/bin/prod/create-recore-config b/bin/prod/create-recore-config
index 953968f..cc9fea8 100755
--- a/bin/prod/create-recore-config
+++ b/bin/prod/create-recore-config
@@ -47,12 +47,26 @@ fi
 info "Hardware revision: ${HW_REV}"
 info "Serial number: ${SNR}"
 
-if [[ ! `wget -NS --spider $URL 2>&1 | grep 'HTTP/1.1 200 OK'` ]]; then
-  echo "Unable to find the calibration file at the remote location: $URL".
-  exit 2
+# wget's own exit codes distinguish "couldn't reach the server at all"
+# (4 - network failure: no internet, DNS, connection refused, etc.) from
+# "reached the server but it returned an error" (e.g. 8, a 404 - no
+# calibration file for this serial). Report those two cases separately
+# rather than a single generic "unable to find" message either way.
+if wget -q --spider "$URL"; then
+  WGET_STATUS=0
+else
+  WGET_STATUS=$?
 fi
 
-info "Calibration file valid"
+if [ "$WGET_STATUS" -eq 0 ]; then
+  info "Calibration file valid"
+elif [ "$WGET_STATUS" -eq 4 ]; then
+  echo "No internet connection. Setting the serial number requires internet access to download the calibration file."
+  exit 3
+else
+  echo "No calibration file found for serial number ${SNR}. Please check the serial number is correct."
+  exit 2
+fi
 
 DEV=`lsblk -n -o NAME | grep 'mmcblk[0-2]$'`
 DEV_BOOT="/dev/${DEV}boot0"
diff --git a/reflash/server.go b/reflash/server.go
index 31b3cce..296b3f8 100644
--- a/reflash/server.go
+++ b/reflash/server.go
@@ -1138,7 +1138,16 @@ func updateConfig(w http.ResponseWriter, r *http.Request) {
 	var data *UpdateConfigCommand = &UpdateConfigCommand{}
 	reqBody, _ := io.ReadAll(r.Body)
 	json.Unmarshal(reqBody, &data)
-	_, _, err := runCommand2("create-recore-config", strconv.Itoa(data.Snr))
+	out, _, err := runCommand2("create-recore-config", strconv.Itoa(data.Snr))
+	// create-recore-config prints a specific, user-facing reason (missing
+	// calibration file vs. no internet connection) before exiting non-zero -
+	// surface that instead of the generic "exit status N" from err.
+	if err != nil {
+		lines := strings.Split(strings.TrimSpace(out), "\n")
+		if lastLine := lines[len(lines)-1]; lastLine != "" {
+			err = fmt.Errorf("%s", lastLine)
+		}
+	}
 	sendResponse(w, err)
 }