I used "saverom att143.rom 16" to make a 16KB file... hopefully it grabbed the right thing. So, I offer
no guarantees that the file will work, but I have it for you to try. You'll need to split it in order to write it to chip, but that shouldn't be too difficult. If you do not have success with it, get back to me and I'll make an attempt at a different method of dumping it.