I experience the same bug. Updated one of the 2 modems from server, then can't update the other one, the update button being disabled when I choose that other modem (actually it's disabled for both modems, it makes sense for the updated one, but not for the not updated one).
RUTX12 running RUTX_R_00.02.05.1
Primary modem firmware version EG06ELAR03A05M4G
Secondary modem firmware version EG06ELAR04A04M4G
Is there an ETA on this bug fix?
Thanks and kind regards.
P.S.
Very nice product RUTX12. Thanks a lot for making it, for its UI and for its documentation.