I found a workaround by myself.
simply copied /lib/modules/3.14.28/extra/bcmlinuxdvb.ko from openpli 7.0 to the same folder of openpli 7.1 and now all the cards are correctly read from internal reader.
I don't know what kind of downside this lead to the system (cause this module I think it covers also other features, not only card reader), but for card reading capabilities now it seems ok.
To all the developers: could you please give some feedback on this and eventually investigate on the difference between the two module versions in order to make things correctly ?
Thanks