diff --git a/tests/zfs-tests/tests/functional/rsend/send-c_volume.ksh b/tests/zfs-tests/tests/functional/rsend/send-c_volume.ksh
index 988ed91b9918..1bf234823459 100755
--- a/tests/zfs-tests/tests/functional/rsend/send-c_volume.ksh
+++ b/tests/zfs-tests/tests/functional/rsend/send-c_volume.ksh
@@ -29,6 +29,7 @@
 
 function cleanup
 {
+	rm $BACKDIR/copy
 	log_must_busy zfs destroy -r $vol
 	cleanup_pool $POOL2
 }
@@ -60,7 +61,9 @@ log_must eval "zfs recv -d $POOL2 <$BACKDIR/full"
 
 verify_stream_size $BACKDIR/full $vol
 verify_stream_size $BACKDIR/full $vol2
-md5=$(dd if=$voldev2 bs=1024k count=$megs 2>/dev/null | md5digest)
+block_device_wait $voldev2
+log_must dd if=$voldev2 of=$BACKDIR/copy bs=1024k count=$megs
+md5=$(md5digest $BACKDIR/copy)
 [[ $md5 = $md5_1 ]] || log_fail "md5 mismatch: $md5 != $md5_1"
 
 # Repeat, for an incremental send
@@ -72,7 +75,9 @@ log_must eval "zfs recv -d $POOL2 <$BACKDIR/inc"
 
 verify_stream_size $BACKDIR/inc $vol 90 $vol@snap
 verify_stream_size $BACKDIR/inc $vol2 90 $vol2@snap
-md5=$(dd skip=$megs if=$voldev2 bs=1024k count=$megs 2>/dev/null | md5digest)
+block_device_wait $voldev2
+log_must dd skip=$megs if=$voldev2 of=$BACKDIR/copy bs=1024k count=$megs
+md5=$(md5digest $BACKDIR/copy)
 [[ $md5 = $md5_2 ]] || log_fail "md5 mismatch: $md5 != $md5_2"
 
 log_pass "Verify compressed send works with volumes"