is it possible!????????

is there a software which can change/edit firmwares??????????????

not really. the closest thing that can do this is patches

I think not, because the most firmware are encrypted.

Nice day

and to reflash them?

and to refkash them?

tweak yor phone by uploading patches in xss++.

Yes it is possible but not only with one software and not only with software.
What do you want to change or edit in firmware and why?
Please answer and prevent me to put here gsm cable schematics, gsm software and everything what you need for this job.

FAR if u can

well u cant,but u still can customize it using cusom patches and menu.ml and layout.xml,u can use far manager,but there is no wide changes in it

one of the reasons is that i want a better media player on my k800(maybe a walkman tipe player)

sometimes you can just flash a different firmware on your phone to get the functions you want (like the k750i can be flashed to, if i remember right, a w800i perfectly fine). usually though, if you flash it with a different phones firmware, not everything will function correctly. But as for modding your firmware to add a media player, this cannot be done. I don't know if it ever will be possible, but its a no for now.

i think it's a very difficult thing to do that you must have experience to do that i think