When you connect Gammu to phone, it does several checks on phone (I'm
currently talking especially about AT based connections). Some of these
checks might result in suggestions on improvements in configuration
either in code or configuration. However they are a bit hidden - you
need to enable debug log to actually see them.
One of those hints might allow Gammu to do much more with your phone:
HINT: Please consider adding F_OBEX to your phone capabilities in common/gsmphones.c
F_OBEX will tell Gammu, that phone can be switched to OBEX mode,
which might provide access to more features than generic AT mode.
The word might is important here, because for some phones OBEX does not
bring anything new and using it only hides some AT functionality. This
is also reason, why switch is not done automatically and you must change
sources to do this. I'd gladly accept patches, if you have successfully
tested F_OBEX with your phone!