diff --git a/artiq/gateware/test/rtio/test_dma.py b/artiq/gateware/test/rtio/test_dma.py
index 5e4115279..759fe60b0 100644
--- a/artiq/gateware/test/rtio/test_dma.py
+++ b/artiq/gateware/test/rtio/test_dma.py
@@ -23,7 +23,7 @@ def encode_record(channel, timestamp, address, data):
     r += encode_n(channel, 3, 3)
     r += encode_n(timestamp, 8, 8)
     r += encode_n(address, 2, 2)
-    r += encode_n(data, 4, 64)
+    r += encode_n(data, 1, 64)
     return encode_n(len(r)+1, 1, 1) + r
 
 
@@ -37,24 +37,45 @@ def pack(x, size):
                 n |= x[j]
             except IndexError:
                 pass
-        # print("{:0128x}".format(n))
         r.append(n)
     return r
 
 
-test_writes = [
+def encode_sequence(writes, ws):
+    sequence = [b for write in writes for b in encode_record(*write)]
+    sequence.append(0)
+    return pack(sequence, ws)
+
+
+test_writes1 = [
     (0x01, 0x23, 0x12, 0x33),
     (0x901, 0x902, 0x911, 0xeeeeeeeeeeeeeefffffffffffffffffffffffffffffff28888177772736646717738388488),
     (0x81, 0x288, 0x88, 0x8888)
 ]
 
 
+test_writes2 = [
+    (0x10, 0x10000, 0x20, 0x77),
+    (0x11, 0x10001, 0x22, 0x7777),
+    (0x12, 0x10002, 0x30, 0x777777),
+    (0x13, 0x10003, 0x40, 0x77777788),
+    (0x14, 0x10004, 0x50, 0x7777778899),
+]
+
+
+prng = random.Random(0)
+
+
 class TB(Module):
     def __init__(self, ws):
-        sequence = [b for write in test_writes for b in encode_record(*write)]
-        sequence.append(0)
-        # print(sequence)
-        sequence = pack(sequence, ws)
+        sequence1 = encode_sequence(test_writes1, ws)
+        sequence2 = encode_sequence(test_writes2, ws)
+        offset = 512//ws
+        assert len(sequence1) < offset
+        sequence = (
+            sequence1 +
+            [prng.randrange(2**(ws*8)) for _ in range(offset-len(sequence1))] +
+            sequence2)
 
         bus = wishbone.Interface(ws*8)
         self.submodules.memory = wishbone.SRAM(
@@ -64,16 +85,19 @@ class TB(Module):
 
 class TestDMA(unittest.TestCase):
     def test_dma_noerror(self):
-        prng = random.Random(0)
         ws = 64
         tb = TB(ws)
 
-        def do_dma():
-            for i in range(2):
-                yield from tb.dut.enable.write(1)
+        def do_dma(address):
+            yield from tb.dut.dma.base_address.write(address)
+            yield from tb.dut.enable.write(1)
+            yield
+            while ((yield from tb.dut.enable.read())):
                 yield
-                while ((yield from tb.dut.enable.read())):
-                    yield
+
+        def do_writes():
+            yield from do_dma(0)
+            yield from do_dma(512)
 
         received = []
         @passive
@@ -98,5 +122,5 @@ class TestDMA(unittest.TestCase):
                     self.fail("unexpected RTIO command")
                 yield
 
-        run_simulation(tb, [do_dma(), rtio_sim()])
-        self.assertEqual(received, test_writes*2)
+        run_simulation(tb, [do_writes(), rtio_sim()])
+        self.assertEqual(received, test_writes1 + test_writes2)