Oche Oche Oche empty results (and RAM/ROM hacking of it)

[dondplayer]

This is a follow on from the thread titled 'Just an idea' by @Levartemit

So first about the empty itself which I have been doing on and off over the last few days by hacking the RAM using the FME debugger:

It's an awkward empty to do. Firstly so many of the reel positions have numbers on them so being able to get all 3 Jackpot symbols in line without needing to spin out at least one reel is a game of pure luck. When you do get it and it puts you on the board it knows not to give you a good number on the cash side (for MS) and will only ever give 2 bullseye symbols (you need 3 for MS) from the darts shots. Well that's my experience from the three jackpots I got. What you can do is try for 3 triple bars (or double bars) from the superhold if they are available instead. That's £15 for triple bars and you often get a chance to win a gamble on the cash side up to £20. Other times it just throws you on the feature board so you just take the most you can - usually off the darts shots.

STOP THE PRESS - it's not an infinite empty but I was about £250 up at one point. So after the 3rd jackpot it did an Alien special and would not board for £65 and that includes not giving a bonus because you can board from other options on the bonus with the slow down. Being as the hoppers on them were £350 if full it would class as an empty I guess.

Now onto the RAM/ROM hacking:

I definitely could write a fairly seamless RAM hacker for this that would need the debugger open. I might be able to write a seamless RAM hacker for this that would NOT need the debugger open - not sure.

As for hacking the ROM - I had a look using the FME debugger and there's just too much going on so I used ghidra as provided by @johnparker007 to look at the code. I looked at the disassembly of the functions and I could identify those that obviously are doing hardware checks. But the others mainly seemed to be just shifting variables around and I really couldn't follow it at all. When I used to do Z80 stuff I knew what I was looking for before I looked at the actual code - with this I don't - I mean I'll have to get some clues from John at a later date like identifying what relates to communicating with the alpha or what relates to reading a keyboard input, etc. On this I was going to use a different approach and that was find the routine that's cycling through the bonus options then see if there's a bit that doesn't call the superhold bit - but even that might be a list and it just ignores the last option or something - so that could be a count of 1 difference - not 02 where looking for the reading of the stake.

[Levartemit]

@dondplayerGreat work! Hope its something that can be released as a general layout at some point. My quest for BFM superhold will continue  

[thealteredemu]

@Levartemit I’d argue we already have some roms that will allow the super hold trick but maybe something to do with how hold inputs are implemented.  Most standard keyboards suffer from ghosting etc.

Maybe an iPac usb button setup would be a better way to test if this is the case.

J

 

[thealteredemu]

@dondplayer Great stuff.

Ah, you have z80 skills.

Well, I’ve been working on a project.  So I have a Bullseye 10p rom that has the unlimited bullseye trick working.  I did look at the chipped version and managed to unchip that version, it took me a good while as I don’t really understand z80.  In the end it looked like a separate attract mode was added.  Anyway I cracked it in the end.

Id really like to put the emptier back in the 20p version, I’ve tried a few things but it doesn’t look as straight forward as the 5p/10p.

If you fancy a quick poke around let me know, I can send you the 10p version that has the bug and the 10p version I hacked to offer the same bug so you can see what I did.  Also I can send the 20p version.

It looks like they added the same kind of fix as this version like the chipped 10p version has the extra alpha information.

IE Thry both have 2 ‘You Require’ in the rom as opposed to the unchipped 10p version that only has a single ‘You Require’

Anyway let me know, I’m still plugging away when I get chance but I think it’s outside of my current knowledge.

J

 

[dondplayer]

26 minutes ago, Levartemit said:

My quest for BFM superhold will continue  

What's the issue with BFM superhold ?

Going by @thealteredemu response is it something to do with trying to hold down multiple keys at once ?

[Levartemit]

On the real machine if unchipped when you got SH you could hold the reels at the top or bottom of the movement as normal. If you then pressed cancel then one of the hold buttons immediately after, the remaining reels would step a position or two beyond the original frame. You could then work all the reels around to JP and collect. Snake rattle and roll had SH 2nd feature up so was swiftly chipped. Cop the lot could offer it randomly or off a bonus. LOTR only offered it randomly during play, despite it having a feature called reels of fire that had a SH in it, but it never worked, like it used a different script.

It has been said that there may be unchipped ROMs available but the emulator can't interpret the key presses the same way the machine did in this instance. I'm not sure about that as it works fine for things like wedges.

[logopolis]

53 minutes ago, thealteredemu said:

@Levartemit I’d argue we already have some roms that will allow the super hold trick but maybe something to do with how hold inputs are implemented.  Most standard keyboards suffer from ghosting etc.

Maybe an iPac usb button setup would be a better way to test if this is the case.

J

 

Same with Snake Rattle And Roll super hold empty.

[thealteredemu]

Yeah, I've done both Snake and LOTR in the arcade.

Were these £25 OG releases or was there £15 versions released first for any of these machines?

J

 

 

[johnparker007]

4 hours ago, dondplayer said:

I mean I'll have to get some clues from John at a later date like identifying what relates to communicating with the alpha or what relates to reading a keyboard input, etc.

I did post a rough strategy for reimplementing the hack, not as clean as removing the original code they added - but it would work I think:

If you read that post and the one directly below, that tells how to go about detecting whether the flashing bonus is active, running your own extra code if so to change the stake down to 25p, and also how to disable the ROM checksum test to allow you to make changes without it alarming at startup - hope that helps  

[dondplayer]

10 minutes ago, johnparker007 said:

I did post a rough strategy for reimplementing the hack, not as clean as removing the original code they added - but it would work I think:

If you read that post and the one directly below, that tells how to go about detecting whether the flashing bonus is active, running your own extra code if so to change the stake down to 25p, and also how to disable the ROM checksum test to allow you to make changes without it alarming at startup - hope that helps  

Yes John I followed the idea at the time but I wanted to try and make it as much like the original so I rethought about it and decided if I could find the part that basically said 'if on pound stake don't include the superhold option whilst cycling through the others' I would see if that could be fixed by changing just one byte potentially. But it depends how that's done - as I said it could be a list of items as such and the same routine is used over and over.

I know you are busy at the moment but I might come back to you at a later date with some (what will seem to you) basic questions. You could say - wait for it - I am after some pointers

BTW thanks again for the initial identification of the stake memory location and how to sort the checksum if I do have a go at this ROM.

[Levartemit]

19 hours ago, thealteredemu said:

Yeah, I've done both Snake and LOTR in the arcade.

Were these £25 OG releases or was there £15 versions released first for any of these machines?

J

 

 

SRR and LOTR I'm sure had £15 releases first, though it was late on. The jump from £10 to £25 on the cash ladder is the tell.

[thealteredemu]

So we might find a non switchable lotr release.  We only seem to have one version of srr so that’s likely from bulletin board and most certainly fixed.

I could rig my iPac up from my arcade cab and make a makeshift button setup their shouldn’t be any ghosting on this I hope.

J

[logopolis]

We have 2 versions of Snake. 

Snake Rattle Roll.zip

[thealteredemu]

Think one is data and the other non data, think they are the same version.  I could be wrong I will check them out once I get my button panel sorted out.  Might actually order a new iPac and buttons as maybe I should start dismantling my video cab as I know I’ll never put them back together

Give it a week before I can take a look at this, be nice to have a dedicated button panel

J

Edited August 20, 2025 by thealteredemu

[dondplayer]

Here's a short showing the JP superhold and the Mega Streak on Oche! Oche! Oche! that I recorded the other day. Usually it won't let you get the MS but the steps meant it trapped itself.

Coincidentally it looks like the modified ROM might not be far away going by a comment by @johnparker007 in another thread.

 

 

[dondplayer]

Well for anyone who wants to have a play I've done a hack of the ROM so the superhold bonus is now available on £1 play - attached.

I say I but it's a big thanks to @johnparker007 who has already said how to bypass the checksum and gave me a handy way of knowing when the code is in the bonus routine.

So for 25p or 50p play there is no change in behaviour - I've tested it on all 3 stakes and seems to be all good. Did make a schoolboy error on one run where the 25p stake magically became £1 stake 

Technical info:

Although memory location FFFF1185 seems unused it's being read up along with FFFF1184 so I used FFFF1124 as a storage location. This is easy to change in the new bit of code I've written should it be discovered it is in use.

As I've said before I'm an amateur Z80 programmer from the late 80s so this has been a challenge - it's took hours to learn the 68000 mnemonics and write some simple code using EASy68K to get the actual machine code values. Probably have taken John minutes to do what I have Today but I had a free day so it's all been good

 

OCI71_0K_SH.zip

[thealteredemu]

Well done with this bud

J

[johnparker007]

17 hours ago, dondplayer said:

Well for anyone who wants to have a play I've done a hack of the ROM so the superhold bonus is now available on £1 play - attached.

I say I but it's a big thanks to @johnparker007 who has already said how to bypass the checksum and gave me a handy way of knowing when the code is in the bonus routine.

So for 25p or 50p play there is no change in behaviour - I've tested it on all 3 stakes and seems to be all good. Did make a schoolboy error on one run where the 25p stake magically became £1 stake 

Technical info:

Although memory location FFFF1185 seems unused it's being read up along with FFFF1184 so I used FFFF1124 as a storage location. This is easy to change in the new bit of code I've written should it be discovered it is in use.

As I've said before I'm an amateur Z80 programmer from the late 80s so this has been a challenge - it's took hours to learn the 68000 mnemonics and write some simple code using EASy68K to get the actual machine code values. Probably have taken John minutes to do what I have Today but I had a free day so it's all been good

 

OCI71_0K_SH.zip 2.66 MB · 4 downloads

Great work, good to see others getting into this stuff more, since there's lots of ROM hacks that could be done   I do need to do more of that tutorial series I started when I get some free time...

[Sarkymark77]

Pretty nuts!