diff --git a/artiq/test/gateware/drtio/test_full_stack.py b/artiq/test/gateware/drtio/test_full_stack.py
index bf22d8e8d..79833256e 100644
--- a/artiq/test/gateware/drtio/test_full_stack.py
+++ b/artiq/test/gateware/drtio/test_full_stack.py
@@ -1,10 +1,12 @@
 import unittest
 from types import SimpleNamespace
+import random
 
 from migen import *
 
 from artiq.gateware.drtio import *
 from artiq.gateware import rtio
+from artiq.gateware.rtio import rtlink
 from artiq.gateware.rtio.phy import ttl_simple
 from artiq.coredevice.exceptions import *
 
@@ -33,6 +35,14 @@ class DummyRXSynchronizer:
         return signal
 
 
+class LargeDataReceiver(Module):
+    def __init__(self, width):
+        self.rtlink = rtlink.Interface(rtlink.OInterface(width))
+        self.received_data = Signal(width)
+        self.sync.rio_phy += If(self.rtlink.o.stb,
+            self.received_data.eq(self.rtlink.o.data))
+
+
 class DUT(Module):
     def __init__(self, nwords):
         self.ttl0 = Signal()
@@ -45,9 +55,11 @@ class DUT(Module):
         rx_synchronizer = DummyRXSynchronizer()
         self.submodules.phy0 = ttl_simple.Output(self.ttl0)
         self.submodules.phy1 = ttl_simple.Output(self.ttl1)
+        self.submodules.phy2 = LargeDataReceiver(512)
         rtio_channels = [
             rtio.Channel.from_phy(self.phy0, ofifo_depth=4),
-            rtio.Channel.from_phy(self.phy1, ofifo_depth=4)
+            rtio.Channel.from_phy(self.phy1, ofifo_depth=4),
+            rtio.Channel.from_phy(self.phy2, ofifo_depth=4),
         ]
         self.submodules.satellite = DRTIOSatellite(
             self.transceivers.bob, rx_synchronizer, rtio_channels)
@@ -64,11 +76,13 @@ class TestFullStack(unittest.TestCase):
 
         ttl_changes = []
         correct_ttl_changes = [
+            # from test_pulses
             (203, 0),
             (208, 0),
             (208, 1),
             (214, 1),
 
+            # from test_fifo_space
             (414, 0),
             (454, 0),
             (494, 0),
@@ -136,6 +150,15 @@ class TestFullStack(unittest.TestCase):
                 yield from write(0, 1)
             delay(200*8)
 
+        def test_large_data():
+            correct_large_data = random.Random(0).randrange(2**512-1)
+            self.assertNotEqual((yield dut.phy2.received_data), correct_large_data)
+            delay(10*8)
+            yield from write(2, correct_large_data)
+            for i in range(40):
+                yield
+            self.assertEqual((yield dut.phy2.received_data), correct_large_data)
+
         def test_fifo_space():
             delay(200*8)
             max_wlen = 0
@@ -161,11 +184,11 @@ class TestFullStack(unittest.TestCase):
         def test_tsc_error():
             err_present = yield from mgr.packet_err_present.read()
             self.assertEqual(err_present, 0)
-            yield from csrs.tsc_correction.write(10000000)
+            yield from csrs.tsc_correction.write(100000000)
             yield from csrs.set_time.write(1)
-            for i in range(5):
+            for i in range(15):
                yield
-            delay(10000)
+            delay(10000*8)
             yield from write(0, 1)
             for i in range(10):
                yield
@@ -187,6 +210,7 @@ class TestFullStack(unittest.TestCase):
             yield from test_pulses()
             yield from test_sequence_error()
             yield from test_fifo_space()
+            yield from test_large_data()
             yield from test_fifo_emptied()
             yield from test_tsc_error()
 
@@ -203,7 +227,7 @@ class TestFullStack(unittest.TestCase):
                 yield
                 cycle += 1
 
-        run_simulation(dut, 
+        run_simulation(dut,
             {"sys": test(), "rtio": check_ttls()}, self.clocks)
         self.assertEqual(ttl_changes, correct_ttl_changes)