diff --git a/tests/qemu-iotests/039 b/tests/qemu-iotests/039
index 617f3977ccde3fb30e43ad1d0c1dd08ed965d9e0..9e9b379baa986640205b9285c7abee1b9baef7b1 100755
--- a/tests/qemu-iotests/039
+++ b/tests/qemu-iotests/039
@@ -147,6 +147,33 @@ $PYTHON qcow2.py "$TEST_IMG".base dump-header | grep incompatible_features
 _check_test_img
 TEST_IMG="$TEST_IMG".base _check_test_img
 
+echo
+echo "== Changing lazy_refcounts setting at runtime =="
+
+IMGOPTS="compat=1.1,lazy_refcounts=off"
+_make_test_img $size
+
+$QEMU_IO -c "reopen -o lazy-refcounts=on" \
+         -c "write -P 0x5a 0 512" \
+         -c "sigraise $(kill -l KILL)" "$TEST_IMG" 2>&1 \
+    | _filter_qemu_io
+
+# The dirty bit must be set
+$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+_check_test_img
+
+IMGOPTS="compat=1.1,lazy_refcounts=on"
+_make_test_img $size
+
+$QEMU_IO -c "reopen -o lazy-refcounts=off" \
+         -c "write -P 0x5a 0 512" \
+         -c "sigraise $(kill -l KILL)" "$TEST_IMG" 2>&1 \
+    | _filter_qemu_io
+
+# The dirty bit must not be set
+$PYTHON qcow2.py "$TEST_IMG" dump-header | grep incompatible_features
+_check_test_img
+
 
 # success, all done
 echo "*** done"
diff --git a/tests/qemu-iotests/039.out b/tests/qemu-iotests/039.out
index d8c5a44519062152a3336386751dfdc98ec13c09..03a31c5943e0296f49b608a527c12e27cc3bb175 100644
--- a/tests/qemu-iotests/039.out
+++ b/tests/qemu-iotests/039.out
@@ -74,4 +74,22 @@ incompatible_features     0x0
 incompatible_features     0x0
 No errors were found on the image.
 No errors were found on the image.
+
+== Changing lazy_refcounts setting at runtime ==
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
+wrote 512/512 bytes at offset 0
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+./common.config: Killed                  ( exec "$QEMU_IO_PROG" $QEMU_IO_OPTIONS "$@" )
+incompatible_features     0x1
+ERROR cluster 5 refcount=0 reference=1
+ERROR OFLAG_COPIED data cluster: l2_entry=8000000000050000 refcount=0
+
+2 errors were found on the image.
+Data may be corrupted, or further writes to the image may corrupt it.
+Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=134217728
+wrote 512/512 bytes at offset 0
+512 bytes, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec)
+./common.config: Killed                  ( exec "$QEMU_IO_PROG" $QEMU_IO_OPTIONS "$@" )
+incompatible_features     0x0
+No errors were found on the image.
 *** done