recover CRS from version 5

I installed version 5 on my CRS125-24G-1S-RM by mistake.
I was having a lot of problems with 6.7 slow performance.
Very disappointed with this product previously I had a very good experience with Mikrotik but the CRS is pretty bad.
I can login to the console but no ethernet ports come up.
How can I reinstall 6.5 on this?
I tried Netinstall booting other ethernet but the box does not appear.
Its less then a month old btw.
Thanks,
Garry
http://forum.mikrotik.com/posting.php?mode=post&f=2&sid=426f7467fae60a312f8de15a405dae2e#