Here is some software I wrote several years ago to create EPROMs for the Epson 
Geneva. I don't remember much of the software and it is not commented (except 
for the state diagrams I have tucked away in a binder somewhere in my office), 
so you're pretty much on your own with this one.
The software is written in Turbo Pascal in two parts: pxrom.pas is the main 
file, and pxfs.pas is a set of utilities included by pxrom.pas. To compile the 
software, load pxrom.pas into Turbo Pascal and tell it to compile the thing.
The software understands three single-character commands:

    I initializes the EPROM image. The EPROM image is stored in a file named 
    ROM.DAT. The software will ask you for the size of the EPROM in KBytes. I 
    have used this software to generate both 32KB EPROMs for the internal ROM 
    sockets and 128KB EPROMs for the ROM socket in the memory wedge. 
    C copies a file from your CP/M system into the ROM image. It will ask for a 
    file name, read the file, and store it in the ROM image under the same name. 
    
    Control-Z exits the software. 
I have also included a sample EPROM created with the software. This EPROM has 
three files: pxrom.pas, pxfs.pas, and kermit.com. Kermit.com is a copy of 
generic CP/M KERMIT from my DECmate II. I've used it with success on the Geneva, 
but you may have to try a few port settings (I don't recall whether the Geneva 
wants "SET PORT TTY:" or "SET PORT UC1:" to get out the serial port. At any 
rate, this copy of KERMIT is pre-configured to work correctly on the DECmate 
(which I believe uses UC1:) and the default will be wrong for the Geneva).
Be aware that Generic CP/M KERMIT does not transfer binary files, so you'll have 
to UUENCODE them or whatever before sending them across to your Geneva.
For those of you without Turbo Pascal, I've also made a binary copy of the 
software. To get my machine to download it correctly to you, I've given it an 
extenstion of .GIF; remember to change the extension after you download it.
The binary copy was compiled with a Max memory address of 0x8000. I don't know 
if the software will actually run in that little memory (it doesn't do any 
dynamic memory allocation), so good luck.