Rufus does have a replacement bootsector that's used by default. Maybe try without using that special boot sector.
@Carlos can you guide me to how to set rufus up to do that? also I will try the way what Enthousiast sugest but last I tried that it complain that not enough place on an empty fat32 empty disk, I give it a go again once more.
I will also try the way you suggest on formated fat32 usb disk. otherwise if no luck I just make an inplace upgrade with or not keeping all files and setting. I return if need more help not I just dont want giving up.BTW. Guessing its RUFUS give me that problem so I Might go back a rufus version or two when come to that.I want to do the best and easy way to do booting from usb.
You can toggle the Rufus MBR with Alt+A, however, I don't know if it will make a difference in this case.
thanks I TRY, BTW, couldnt extrat the iso image to 16 gb usb using both winrar and 7zip other way I dont know about, also tried mount the iso and copy all to usb but all way it says not enough place on the disk and its full formated fat 32, I try go a few rufus version back and see because I guess its rufus make the problem BUT i,m not expert at all.