i) is there the possibilety to copy the current
Yes, of course. The machine can read the flash rom, after
all (how else would it boot?)
ii) if the flash failes is there any way to get the
As long as you don't overwrite the tiny reflash thingy that's there
on most BIOSes; yes. Do keep an emergency floppy at hand, that you
verified to work, though.
iii) how much time will this take me?
If you know how to write to flash memory, and have the specs that
tell you where the write protect is; not more than 30 minutes or
so. If not --> much much longer.