Quoted from CactusJack:

Concerning the modified rom file to delete the "spot letter" feature of the horseshoe:
I found this 4 year old post from Seymour-Shabow:
http://rec.games.pinball.narkive.com/4UsCL6OW/has-anyone-created-a-new-silverball-mania-rom
I just did the mod to the normal 2732 binary for U2 and it at least passes the Checksum test on the bench (unable to game test at this time).
So, if anyone wants to try the mod and test it, here is the change (Again, as stated by Seymour-Shabow)
Original code in U2 binary:
Address 00A6 = 2A 02 8D 1C 8D
New code for U2 binary:
Address 00A6 = 01 01 20 02 3E
As stated in the old post: The 01 are NOPs (No Operation) commands. The 20 is a Branch Always (02 from Program counter) and the 3E corrects the block of EPROM data to pass Checksum testing.
I state again, this is NOT game tested by me as of yet. Only bench tested to pass power up tests.

Quoted from Quench:

If you're using the ROMset on IPDB, you actually need to edit the U1 ROM: "786-16_1.716". That's where you'll find those data bytes.
What type of EPROMs are you going to program? It will make a difference to how you manage the files and what jumper mods will be required for the MPU board to support your EPROMs.

Quoted from Quench:

Does your MPU board have EPROMs or the original PROMs (which are not reprogrammable)?
Best if you post a clear picture of your MPU board showing your current ROMs so we can advise.

Quoted from Edenecho:

Hello!
I just got a SBM and have topshopped it and have been looking on how to make it slightly harder. I came across the posts here regarding rewriting the rules for removing the "spot letter" from horseshoe loop.
I downloaded the sbm ROMS, and apparently the 786-17_2.716 is the U2. I have opened the ROM in a hex editor, but cant seem to find the sequence mentioned above. Any tips on how to do this? Is it not as easy as replacing the values mentioned above, saving the ROM file and then burning the ROM onto an EPROM? :O
Is the sequence of 2A 02 8D 1C 8D supposed to be found as a line inside this? See attached photo.
Sorry for naivity vid1900
[quoted image][quoted image]

Quoted from Quench:

If you're using the ROMset on IPDB, you actually need to edit the U1 ROM: "786-16_1.716". That's where you'll find those data bytes.

Quoted from Quench:

Yes please, a picture of the MPU board only so I can see more detail and close ups of the ROMs at U2 and U6.

Quoted from Quench:

It's just the editor you're using. 2A 02 8D 1C 8D is at the correct offset of address 00A6 so that's it.

Not yet, if I get a clear enough picture of the MPU board showing the jumpers I may be able to determine the ROM types you have.

Quoted from Quench:

Here's an example old picture showing wire jumpers for a particular ROM configuration type. I'm looking for how and where your jumpers are installed that will indicate your ROM type.
[quoted image]

Quoted from Quench:

The front of the board is missing some jumper links. I'm going to presume someones soldered them on the back and from what I see you possibly have 2732 EPROMs - removing the labels will tell you.
To reprogram them, you need an ultraviolet eraser to blank them and of course an EPROM programmer to program the new data in them. Do you have access to these equipment?

Quoted from msarac:

Here's a little step by step I put together when I was trying to figure this out - maybe it will help.
1) Download official ROMS and open 786-16_1.716 in a hex editor.
2) Find offset A6 (Row 000000A0 and column 06) and change the entries to match the code below.
Offset A6 old code: 2a 02 8d 1c 8d change to:
Offset A6 new code: 01 01 20 02 3e
3) If board is running 3 ROMS just burn and replace U1.
4) If board is jumpered for 2 ROMS, (U2 and U6) you need to combine the modified U1 and stock U2 files into one file:
From a DOS prompt, change to the directory with the files and type:
copy /b 786-16_1.716 + 786-17_2.716 u2.732
5) Burn the resulting u2.732 file and put the ROM in U2.