I just want to add to this thread because finding jaguar info for this is practically non-existent lol. This is a great write up but it could use some extra info on a few things.
I recently took advantage of the massive cybermorph carts available. I found that for the 700700-2 there are 2 versions. You have (2) 42 hole pcb's that take the m27c160 eproms, those have blacker shells. Then you have the grayer shells which contains (4) 32 hole pcb's.
I managed to find a 512 KB eprom in a google image which was an mx27c4000 which you can't buy anymore, easily anyhow. I found that am27c040 is a good alternative. At least this way you can make 2MB games.
Now there was no cut and dry spelled out info on splitting the rom into 4 files. But when using romsplit it does give you a glossary, I used it and I was able to get 4 working u files.
I have to use dosbox so I will post my entire procedure that needs to be used. In case you need to use dosbox too "64 bit system".
First I made a folder in c: called dosbox. This is where I put my roms that need to be split and romsplit.exe
1. open dosbox
2. type mount c: c:\dosbox
3. type c:
now you are in dosbox folder
4. type romsplit
this will bring up the romsplit program "picture below"
for splitting 2 files I type
romsplit gamerom.j64 -we the (2) is default for 2MB games and I have found if you don't type (4) for 4MB games it fixes it for you anyhow and splits the 4MB games into (2) 2MB hi lo files.
for splitting 4 u1-4 files I type
romsplit gamerom.j64 -bwe
I am unsure if all of those needed entered as I am very novice at this program but it did successfully produce 4 files that worked on a 4 chip 32 hole donor pcb.
I was looking for a 32 dip 1MB eprom but it does not appear to be one based on the way eproms are designed, they do not have a vpp at pin 1 but an A19. Now here are a few usefull images.