Which Donkey Kong 64 Maintains Save?

[sanni]

does the Everdrive not let you just use a virgin rom anyway and save to the 16k eeprom?

No because DK64 has a 6105 cic and the Everdrive has a 6102 + bootemulator. Apparently DK64 detects the bootemulator and therefore you need a crack. The same applies to Jet Force Gemini and Banjo Tooie.

[link83]

Sorry to bump this thread, but i'm curious about this 'security' used on Donkey Kong 64.

I have read about the well known security features in Jet Force Gemini and Banjo-Tooie, but was not really aware of any problems with Donkey Kong 64. Until this thread I had only heard save problems mentioned in a couple of old forum threads, which ended with someone saying it was due to a problem with the original dump, and not due to added security :shrug:

So my question is - how is the game making these security checks? Is it checking for the presence of an original 16k EEPROM chip (In which case I imagine it should really work without being patched on the EverDrive 64) Or is it checking for a CIC-NUS-6105 like Jet Force Gemini and Banjo-Tooie?

Also, i'm guessing that the reason 'Force SRAM' has to be used is due to the original patches being designed for use with old copiers that used SRAM for saves? So would it be possible to remove the security whilst leaving the save type as 16k EEPROM, and if so is anyone working on this?

Thanks in advance for any info :nod:

[fathertime]

Sorry to bump this thread, but i'm curious about this 'security' used on Donkey Kong 64.

I have read about the well known security features in Jet Force Gemini and Banjo-Tooie, but was not really aware of any problems with Donkey Kong 64. Until this thread I had only heard save problems mentioned in a couple of old forum threads, which ended with someone saying it was due to a problem with the original dump, and not due to added security :shrug:

So my question is - how is the game making these security checks? Is it checking for the presence of an original 16k EEPROM chip (In which case I imagine it should really work without being patched on the EverDrive 64) Or is it checking for a CIC-NUS-6105 like Jet Force Gemini and Banjo-Tooie?

Also, i'm guessing that the reason 'Force SRAM' has to be used is due to the original patches being designed for use with old copiers that used SRAM for saves? So would it be possible to remove the security whilst leaving the save type as 16k EEPROM, and if so is anyone working on this?

Thanks in advance for any info :nod:

The ROM released at the time by the scene group "Aggression" was a good dump but yes, the copiers back then (v64 with DX256/DS1 and the Z64) only supported the smaller eeprom or else the larger SRAM. This explains the save type redirection required.
The same type of crack/save redirect fix was done by LaC for Zelda Majoras Mask.

You could run a file compare of the unpatched and patched to see what lines of code in a N64 disassembler were modified in the old cracks. Actually LaC's 101% crack for Donkey Kong has the crack code uncompressed in it (the intro is compressed).

I guess Rare were either checking for the 6105 in-game but I doubt it because they didn't do that for Perfect Dark released later. So perhaps they were checking for "tampering" with the save memory in game or else checking for a modified area of the ROM...

Not sure it even needs a crack though with a bootemu (virgin ROM) and 16k eeprom save cart?

Have a read of the .nfo files of those old cracks, also the the scroller on the intros and try to get in touch with the individuals LaC or Titanik :)

[fathertime]

If you were considering looking into this yourself, get the libultra.lib file from the last psy-q dev kit and run another tool "LFE" against the ROM and lib. This will spit out a file telling you the address where the psy-q functions (including the save functions) are in the ROM. Run that against the original virgin ROM and then see how LaC patched them in the patched ROM..

[sanni]

If it would only check for tampering or the 16k eeprom then it should work uncracked on the everdrive 64. But people were reporting that it doesn't maintain the save so it must check for the 6105 sometime after the boot.

Either that or the eeprom emulation in the Everdrive is not 100%

[link83]

Have a read of the .nfo files of those old cracks, also the the scroller on the intros and try to get in touch with the individuals LaC or Titanik :)

I tried comparing the two versions with a hex editor but there were too many differences for me to tinker with, and as i'm no good with coding there wouldn't be any point in me looking at the Psy-Q files.

...So instead I took up your final suggestion and got in touch with LaC to see if he would be interested in changing his cracks so as to keep the original 16k EEPROM save type. I also explained that the cracked version does run, but only if 'Force SRAM' is used. Below is LaC's reply:-

I just looked at the crack code, it's supposed to not convert to sram if 16kbit eeprom is present. But ya i checked on the 64drive, and it doesn't appear to work with 16kbit eeprom is forced. Not sure why. It's possible it never worked.
It is unlikely I will fix it.
Really you can just run with sram set, so whats the problem?

My reply:-

Thanks for your reply. I dont know about the 64drive, but on the EverDrive 64 you still need to use your cracked version of the game, otherwise the save file is deleted after playing for a while. If it saves fine on the 64drive, then might this be a problem with the EverDrive's boot emulator?

Could I just ask if Donkey Kong 64's security is based on checking for the presense of a CIC-NUS-6105 (Like Jet Force Gemini and Banjo-Tooie) or is it checking for something else?

Without the save redirect the game would be easier to run, since the EverDrive 64 requires the user to select 'Force SRAM' every time the cracked Donkey Kong 64 is loaded. It would also make the save file interchangeable with emulators with no alteration needed. I do understand though that i'm asking a lot, as i'm sure it wasn't easy to patch the first time!

Would you mind if I copied your reply in the thread I linked to previously? It was suggested there that I try to contact you or Titanik, so it would be nice to be able to post your answer.

Last message from LaC:-

Ya there is probably something wrong with its bootemu.
There is not copy protection like JFG and Tooie. The dk64 copy protection just checked for valid bootcode in the rom.
If you want to use the save file with other emulators, all you have to do is grab the first 2k of data from the sram save file.
The saving/booting works fine with the 64drive, I suggest people get one of those. :)
Ya I don't mind if you post my reply.

Thanks to LaC for the info, and for letting me post it here :-)

So Donkey Kong 64 doesnt have any copy protection and so shouldn't 'require' a CIC-NUS-6105 like Jet Force Gemini and Banjo-Tooie. It seems like there may be some slight issue with the EverDrive 64's boot emulator? (Or maybe the 16k EEPROM emulation?) and thats possibly why the cracked version is necessary :shrug:

...Maybe KRIKzz would like to look into this? :confused:

[KRIKzz]

i think that boot emulator can not be a problem, but eep16 implementation may contain a problem. well, i just will connect original eeprom16 chip for check this. also you should remember that dk does not show the problem immediately. i play this games few time when ed64 was in development, but save worked fine and i heard about this problem only when somebody said here that he always lost saves in this game

[link83]

Happy to hear you are looking into this KRIKzz :-) I hope you find out whats causing the problem.

Since the save file only dissappears after getting the first crown its not surprising you didn't find any problem. I'm sure nobody expected you to test every game all the way through!

[fathertime]

wow link83, you are relentless :) Very nice of LaC to get back to you and for Krikzz to take interest.

Perhaps LaC might know what causes the save to wipe as there is obviously some sneaky other protection that required him to revisit his original crack and release a final 101% version with this save issue fixed. Perhaps it is more than just "check for tampered boot code in ROM" and it is indeed a test on the 16k eeprom - maybe even some fancy "dongle" style protection where the eeprom in the cart had some bytes preset in the factory ;) I would be interested to hear what is this protection

I've an everdrive64, 64drive and an old v64 here. I think I'll get a copy of an old cart with 16k eeprom and try to use that with with the virgin ROM on the v64 with the 6105 boot emulator by Titanik and again with LaC's 1.1 Boot emu. Lets see if that loses the save.... That will confirm it is indeed a protection involving the eeprom.

Very interesting!

[link83]

Well it would be nice to get to the bottom of this! If you could do some testing fathertime and narrow down the possibilities between the CIC, boot emulator and 16k EEPROM that would be great :nod:

I too wondered why further cracks were needed if there wasnt actually any CIC copy protection in the game, and have actually sent one last message to LaC questioning this.

Since the game loads without problems using the EverDrive 64's boot emulator I think KRIKzz may be right in that this is something to do with the 16k EEPROM emulation. I'm beginning to think that perhaps DK64 saves to the 16k EEPROM chip in an 'unusual' way, so when the game was patched to support SRAM it caused the save file to be deleted at certain points - this wouldnt technically be copy protection. Its either that or Rare purposefully progammed the game this way knowing that many copiers of the time had to save 16k EEPROM to SRAM. If the EverDrive 64 doesnt respond in exactly the same way as the original 16k EEPROM chip, then the save file would also mess up and be deleted.

Your theory about checking for bytes on the 16k EEPROM programmed at the factory is also plausible, but if it were this I would think LaC would mention it?

Definitely worth investigating if you have the time and equipment fathertime :thumbsup:

[C-Kronos]

Donkey Kong 64 (U) [f2].z64 with forced SRAM method works fine for the 64drive as well.

Although, it does crash when the N drops down when trying to use the 16kbit EEPROM.

Any chance we can get the original author of the fix to see if they can work their magic in getting it working properly for all products?

[orac31]

Hi all if I use the correct rom can I play donkey kong to the end? and save or should I dig my cartrige out and play just in case

[discomike]

What am I doing wrong?

ED64 arrived yesterday. After a bit of a fiddle with a few roms, I sat down and had a go at DK64. I used "Donkey Kong 64 (U) [f2].z64" as per FAQ. To start it: I highlighted it, and pressed the bumper buttons until "Force SRAM" was visible, then pressed start. I played the game for over an hour and saved in-game. I Reset the console and restarted the game using same method to check the save had worked.

Unfortunately it had not, the slot was empty, and no save file was created in ED64\SAVE

Thanks to anyone who can help.

[discomike]

After some more experimentation I've still not made any progress. Force SRAM must be wokring to a point as the rom fails to start without it (that is if an .eep save exists), it just doesnt save back to a file upon reset.

I've even tried changing the rom header to another SRAM game to negate the need to force the save type, but that didnt make a difference.

I have tried other SRAM games, such as 1080, and that works fine.

After that I resorted to trying older OSes, but still no luck

Hmpf.

[Nintendo64]

Hi,

I am also looking into getting this thing to work. I am using a Pal N64 + Expansion Pak (original) withED64 v2, OS1.22 and the GoodN64 f2 Release. When trying to start the game, only a Dextrose Intro is showing up and freezing, so that I can not start the game. (I changed the Save to: force SRAM (Not 128) and then started the game by pushing the start button.

Does anyone else has the problem that the game won't boot (except for the Dextrose Cracktro?)

I downloaded the 101% Crack and try it out later.

[discomike]

You do need to force SRAM to get past the Dextrose intro. Which proves that "force SRAM" does something, but when I hit reset after playing, no save file is generated.

I guess the ED OS/bootloader will eventually get updated so that the original rom works correctly.

"f2" version seems to work as it should on a 64drive i tried though, when SRAM is forced.

[Nintendo64]

You do need to force SRAM to get past the Dextrose intro. Which proves that "force SRAM" does something, but when I hit reset after playing, no save file is generated.

I guess the ED OS/bootloader will eventually get updated so that the original rom works correctly.

"f2" version seems to work as it should on a 64drive i tried though, when SRAM is forced.

Doesn't work for me. Even if I use Force SRAM, it will hang. I just see the Dextrose Logo and a Red square, but nothing is happening. It seems to instantly freeze

[discomike]

I was using an JAP N64. I'll try it on a PAL model sometime over the weekend.

[C-Kronos]

You do need to force SRAM to get past the Dextrose intro. Which proves that "force SRAM" does something, but when I hit reset after playing, no save file is generated.

I guess the ED OS/bootloader will eventually get updated so that the original rom works correctly.

"f2" version seems to work as it should on a 64drive i tried though, when SRAM is forced.

The clean rom works normally on the 64drive now, as of the latest update. So it's possible..

[KRIKzz]

anybody tried to use original rom with last OS? cuz on the moment of start of this thread OS had a bug in eeprom16 mode, but those bug was fixed many time ago