21MX proms (per request

[dwight]

I would be surprised if it did 1702s and 2708s. Even 2716s have
a slightly different hardware configuration.
1702s require voltages like 50 volts ( I could be a little off ) and
changing address and data lines over wide voltage ranges.
2708s require multiple rail voltages as well as programming voltages.
2716 are that last of the program by turning the programming voltage
on and off.
All the newer chips have a constant programming voltage and
a separate program logic level pin. They can even be read while
the programming voltage is high.
I doubt any would make the special provisions for 1702s. 2708s
are a stretch but if your not doing 2716s it won't be able to
handle 2708 even if it had the extra rail voltages. 
I have a DataIO ( I think a 29B ) and I know it doesn't do 1702s.
In any case, I don't think any of these would be fast enough for
a 21MX boot code. I think these expect it to be faster than 100ns.
Dwight