diff --git a/artiq/test/coredevice/test_rtio.py b/artiq/test/coredevice/test_rtio.py
index 6291a4e60..11204b4ef 100644
--- a/artiq/test/coredevice/test_rtio.py
+++ b/artiq/test/coredevice/test_rtio.py
@@ -248,7 +248,7 @@ class LoopbackGateTiming(EnvExperiment):
         gate_end_mu = now_mu()
 
         # gateware latency offset between gate and input
-        lat_offset = 12*8
+        lat_offset = 11*8
         out_mu = gate_start_mu - loop_delay_mu + lat_offset
         at_mu(out_mu)
         self.loop_out.pulse_mu(24)