Since it appears that the ROM image is in the first part of the file, I wonder if you simply clone on a totally clean system (fresh format, and not "connected" to create the default folders, IF you could bail out on the clone after an hour or so?
The first part is VERY slow to download. I think this is the firmware. Then the speed of down load goes up (at least I saw this when I had WMA files on the unit). I had made a 700mb image, and the thing died
If I look at the resultant file, the first part obviously is the ROM firmware, and then there is a FAT32 section, and then the WMA files start. Thus, since I have formated clean, I am re-running, and when the ROM and Fat32 section have been downloaded, I am going to cancel. I figure if S1clone can rewrite that data in case my unit dies, it will "fix" and the unit will have regained it's firmware.
NOTE I am not dumb enough to "test" this without it being a last resort (i.e. dead unit).
H.