EK/QF/BA online check in

[Per_Travels]

Hi - just wondering if I'm missing something here. I'm flying PER - DXB - DUB - LHR at the moment (typing this from DXB). The PER to DUB flights are QF codeshares on EK metal, whilst the DUB - LHR is BA flight number and metal, all one ticket. When I checked in at PER they were only able to check me in for the QF/EK flights - ie to DUB. As I've got a fairly tight connection in DUB (55 min) I'd like to have a mobile boarding pass for the BA flight. when I try to check in for this flight neither the QF or EK websites seem to allow this, and the BA check in process just sends me back to the QF site (as the initial flight from PER is a QF flight number).

Any ideas for how i can check in and get a mobile boarding pass pior to arriving in DUB?