diff --git a/libraries/AP_ExternalAHRS/AP_ExternalAHRS_LORD.cpp b/libraries/AP_ExternalAHRS/AP_ExternalAHRS_LORD.cpp
index 33c2fe864b..8cd19ea4f3 100644
--- a/libraries/AP_ExternalAHRS/AP_ExternalAHRS_LORD.cpp
+++ b/libraries/AP_ExternalAHRS/AP_ExternalAHRS_LORD.cpp
@@ -111,9 +111,8 @@ void AP_ExternalAHRS_LORD::build_packet()
     WITH_SEMAPHORE(sem);
     uint32_t nbytes = MIN(uart->available(), 2048u);
     while (nbytes--> 0) {
-        const int16_t b = uart->read();
-
-        if (b < 0) {
+        uint8_t b;
+        if (!uart->read(b)) {
             break;
         }