@BartoszP
#6 There are a few posts by mkx and rextended that go rather deep on the matter, I’ll see if I can understand the written or non-written implications and produce something easy to understand and replicate.
http://forum.mikrotik.com/t/new-mac-address-on-the-bridge-after-the-update/177812/1
http://forum.mikrotik.com/t/script-for-setting-locally-administered-mac-address-on-bridges/177344/1
#8 working on it 