Devo12: Using parallel flash via USB (library)?

I want to get rid of flashing the library in my Devo12 every time I change some minor settings... one way is replacing the SPI Flash what will be done next, the other is making the parallel flash accessible via USB.

First I tried to make it readable via USB - no problems.
Then I tried to make it writable in the firmware - no real problems.
Third I had to erase sectors - and this is where my problem starts.
The used parallel flash chip (S29GL128P) has a sector size of 128kB. This means that I can only erase areas of this size.
The file system which is installed via the library uses a sector size of 4kB which is good to handle. But deviation does only read - it never erases something so it has not to care for the physical sector size.
We only have (limited) FAT support in deviation. So the only chance to make the file system writable via USB is to create a file system which has a sector size of 128kB. Deviation should be able to read this.
And if Windows would recognize such a file system we could read and write files to the parallel flash (limited to ~120 files due to the big sector size, but enough for media-, template and language folder and errors.txt, datalog.bin).
I have used utils/mkfat/mkfat.py to create a file system with 128kB clusters (and 4kB sectors) and it seems to work in the tx (although some weird screen behavior which I haven't investigated - most probably due to missing files in the library), but Windows (Vista) does not recognize it and even my favorite tool for examining storage devices (the freeware HxD) does not load it.

So does anybody have other ideas of making the parallel device accessible? I am at my limits...

If interested I can describe what I have done so far, but since it does not work really I won't do that in advance.

The second sounds good, but is far beyond my coding skills.

Maybe the easiest way is to replace the SPI flash (25VF032B80-4L-S2 for 1.80€), - cutting off the pins, desoldering them one by one and soldering a bigger one could be an easy solution at least for all who are able to mod the tx with rf modules.
Can you imagine that this will be supported by deviation? Like "size(SPI)==2MB ? {mount parallel flash and search media folder there} : {get everything from SPI}"? I wanted a method to get rid off the library flashing which has a chance to get into the mainstream code...

You're right in all points.
I also believe the 32Mbit chip will work since it has the same internal structure and command set. The 64Mbit chip only seems to be available in bigger packages (TSOP-20 or something like this).
I actually don't know how big my images are but the media folder contains about 1.5MB which will easily fit into the 2MB additional SPI flash.
For me it is ok to flash the library - I have changed files inside maybe 5 times... but others are developing new themes and might have more headache with that (but they will use the emulator instead).

The Java app sounds really good. Aren't here some Java specialists who could support you?