@@ -33,6 +33,13 @@ def test_serial_after_snapshot(uvm_plain, microvm_factory):
     # looking for the # prompt at the end
     serial.rx("ubuntu-fc-uvm:~#")
 
+    # Start a large transmission before we take the snapshot. This will
+    # saturate the TX buffer of the UART and it might make the guest driver
+    # enable TX interrupts.
+    serial.tx("cat /dev/zero | head -c 100000")
+    # Give the guest time to start the transmission
+    time.sleep(1)
+
     # Create snapshot.
     snapshot = microvm.snapshot_full()
     # Kill base microVM.
@@ -45,9 +52,7 @@ def test_serial_after_snapshot(uvm_plain, microvm_factory):
     vm.restore_from_snapshot(snapshot, resume=True)
     serial = Serial(vm)
     serial.open()
-    # We need to send a newline to signal the serial to flush
-    # the login content.
-    serial.tx("")
+
     # looking for the # prompt at the end
     serial.rx("ubuntu-fc-uvm:~#")
     serial.tx("pwd")