This is OS version 103/101 for Yamaha SU700.

1 x M27C800 is needed for this firmware

To write the EPROM (M27C800) you will need an adapter converter ic socket from DIP40 to DIP42. The cheapest and easiest to find is the TL866 series of USB programmers.

Link to description and user guide for TL866:
https://github.com/mafe72/27c160-tl866-adapter

To check the OS version and run some self tests on the SU700, hold down the SONG and SYSTEM buttons while turning the SU700 on. 
The version will only be displayed for a few seconds.