I don't think there's any way of upgrading to the v2 firmware without J-Edit, and it seems like it's a worthwhile improvement. I just upgraded and it's got some new models that look interesting (they go under "MORE" on the unit), and it fixed the problem I had with the v1.6 firmware.
My guess is that the J-Station is never going to be upgraded that much, simply because it seems to be an out-of-production item. I think that most of what we're seeing is models from the amp line being passed down to the J-Station on the cheap. Every time I read that thing about "your J-Station never becoming obsolete" I think of the episode where Homer Simpson bought a new computer.
Dual-boot systems can be a headache (which is why I just took advantage of the depressed prices on components and the opportunity of having some more cash than usual and built a dedicated box for my music recording) but if you are serious about fiddling with the J-Station, I think it would be worthwhile to try to get it worked out so you can use J-Edit. It makes deep editing extremely easy and very, very fast. Without J-Edit, I doubt I ever would have put my J-Station to any serious use. The factory presets are generally awful, but with some very easy tweaking, you can truly make some very Hi-$$$-sounding patches worthy of a sophisticated, "produced" recording. Until I started running J-Edit, I regarded the J-Station as a joke.
Immediately worthwhile is the access to the speaker models and reverb tweaking, only available in "deep editing." Doing that on-board the J-Station device is onerous.
Really, check it out sometime soon and see if you don't think it'd be worth the effort.