PTP650 not acquiring after firmware upgrade


I've completed firmware upgrades on 2 seperate links successfully but the last link I had to upgrade hasn't gone so well. Upgraded all from software version 01-40 to 01-49. 

I upgraded the far end first like the others, the link didn't come up, so I upgraded the near end. It is using fixed frequencies, but TX and RX are different.

I have rebooted the near end several times and have also waited for an hour to see if the link eventually comes up, but no luck. I cannot gain access yet to far end.

It was originally working at a reduced capacity originally due to interference (around 40Mbps).

I'm assuming it's not linking up because of this interference?

One of the links that worked had worse intereference (but DSO) and it linked up fine.

Any help would be greatly appreciated.