Yeah you can.
Before the card writing function on my GT-11 died I use to upload my sessions from my Mac to KA72.
Its pretty straight forward. Just stick the card into the card slot and then browse to the card in KA72 and upload the data.
With the card writing on my GPS dead I'm stuck using the Windows only Navi data mode for uploading data
You need the Navilink software running to update the firmware and that only runs on Windows.
Something to consider is "Parallels Desktop" or some other software that allows you to run windows on your mac.
I'm typing this right now on a MacBook, with windows XP and Realspeed running on another screen... it really does work well once you get it set up.
I've updated firmware using this setup as well.
That said, there are some more software packages that you can run natively on your mac:
GPSResults
GPSActionReplay
You need a copy of Windows too plus the disk space to install it. Windows runs well on modern Macs. It's a bit technical but not too hard to do. Apple hAve some tech articles on dual booting.
However if you have access to any old Windows computer with a USB port it will probably be quicker to update the firmware on it.
