diff --git a/artiq/gateware/rtio/dma.py b/artiq/gateware/rtio/dma.py
index 20d558672..7f5d27d18 100644
--- a/artiq/gateware/rtio/dma.py
+++ b/artiq/gateware/rtio/dma.py
@@ -110,7 +110,7 @@ class RawSlicer(Module):
                  for i in range(out_size)})),
             If(shift_buf, Case(self.source_consume,
                 {i: buf.eq(buf[i*g:])
-                 for i in range(out_size)})),
+                 for i in range(out_size + 1)})),
         ]
 
         fsm = FSM(reset_state="FETCH")
diff --git a/artiq/gateware/test/rtio/test_dma.py b/artiq/gateware/test/rtio/test_dma.py
index 84bc4a3ff..b67f27db5 100644
--- a/artiq/gateware/test/rtio/test_dma.py
+++ b/artiq/gateware/test/rtio/test_dma.py
@@ -67,6 +67,7 @@ def do_dma(dut, address):
 test_writes1 = [
     (0x01, 0x23, 0x12, 0x33),
     (0x901, 0x902, 0x11, 0xeeeeeeeeeeeeeefffffffffffffffffffffffffffffff28888177772736646717738388488),
+    (0x82, 0x289, 0x99, int.from_bytes(b"\xf0" * 64, "little")),
     (0x81, 0x288, 0x88, 0x8888)
 ]