diff --git a/APMrover2/GCS_Mavlink.cpp b/APMrover2/GCS_Mavlink.cpp
index 09a6e524a3..030e16bca4 100644
--- a/APMrover2/GCS_Mavlink.cpp
+++ b/APMrover2/GCS_Mavlink.cpp
@@ -1584,6 +1584,8 @@ void Rover::mavlink_delay_cb()
     }
 
     in_mavlink_delay = true;
+    // don't allow potentially expensive logging calls:
+    DataFlash.EnableWrites(false);
 
     const uint32_t tnow = millis();
     if (tnow - last_1hz > 1000) {
@@ -1603,6 +1605,7 @@ void Rover::mavlink_delay_cb()
     }
     check_usb_mux();
 
+    DataFlash.EnableWrites(true);
     in_mavlink_delay = false;
 }
 
diff --git a/APMrover2/Log.cpp b/APMrover2/Log.cpp
index 9c8f2add7b..d58ba92dc1 100644
--- a/APMrover2/Log.cpp
+++ b/APMrover2/Log.cpp
@@ -85,9 +85,9 @@ int8_t Rover::dump_log(uint8_t argc, const Menu::arg *argv)
 
 int8_t Rover::erase_logs(uint8_t argc, const Menu::arg *argv)
 {
-    in_mavlink_delay = true;
+    DataFlash.EnableWrites(false);
     do_erase_logs();
-    in_mavlink_delay = false;
+    DataFlash.EnableWrites(true);
     return 0;
 }
 
@@ -510,9 +510,9 @@ void Rover::Log_Write_Vehicle_Startup_Messages()
 // start a new log
 void Rover::start_logging()
 {
-    in_mavlink_delay = true;
+    DataFlash.EnableWrites(false);
     DataFlash.StartUnstartedLogging();
-    in_mavlink_delay = false;
+    DataFlash.EnableWrites(true);
 }
 
 #else  // LOGGING_ENABLED
diff --git a/APMrover2/system.cpp b/APMrover2/system.cpp
index 01656a06d0..ebfe31315a 100644
--- a/APMrover2/system.cpp
+++ b/APMrover2/system.cpp
@@ -540,9 +540,6 @@ uint8_t Rover::check_digital_pin(uint8_t pin)
  */
 bool Rover::should_log(uint32_t mask)
 {
-    if (in_mavlink_delay) {
-        return false;
-    }
     if (!(mask & g.log_bitmask)) {
         return false;
     }