ive found an defs update for jkeys, its got a few extra flash models
its got this in there, i dont know if its what your after
Flash, 11, "28F160", 0xd0, 0x200000, 1, 1, 0, 2, 32, 1
Sector, 11, 32, 0, 0x10000
also, if you have the unbuffered jtag they reccommend the length must be no...