My Micro problems

I'm working on a project of reuse of uPs. With all the talk of uPs for different things I thought I'd tell my story. I've located a number of nice stepper motors and controllers. These have L298 H-bridge and L297 stepper chips. It is run by a 68HC711E9 chips. I look this up and it is a neat processor. All kinds of timer functions and such. First problem is that most of these are OTP ( One Time Programmable ). I can live with that but the part is also obsolete. Well to cut part way to the end, I've found some un-programmed parts to work with and one windowed device. Along the way to find good ones, I thought I'd try the china chips. It was not a good idea as I thought. These were all previously programmed. Not exactly what I was looking for. I considered these chips to be worthless for my project ( 4 of these controllers ). Oh, I should mention, the controllers were originally intended for controlling valves. The firmware was only designed to stop in 12 positions ( out of 400 possible for the stepper motor ). This means, even if I setup a program to talk to the original code is not useful. Now back to the used ones I got. I figured, maybe there is a way to use them. A careful check shows that they'd only used 4K of the 12K available. Now all I need to do is find a way to get it to boot my code instead of the original. Scanning the first bytes, I found 3 0FF's in a row. Just enough to put a JMP instruction. It is only 1A hex from the original reset code. The OTP part can be programmed from 1 to 0 so I can reprogram this part. I figure for less than 10 clocks, I can jump into unused OTProm. The interrupt vectors are a little tougher but by the time I need them, I should be able to put vectors in the RAM with low number addresses that I can setup the vectors too. As long as 8K is enough for my code, I can work around a partly used part. I've still got code to write but I can now play with these and not worry as much about new revs to fix any bugs. Dwight