Anyone fancy cracking Dracula Island?

reminisce about bbc micro & electron games like chuckie egg, repton, elite & exileRelated forum: adventures


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leenew
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Anyone fancy cracking Dracula Island?

Post by leenew » Sat Sep 21, 2019 4:57 pm

Hi,
It has been pointed out that Dracula Island adventure from Kansas Software doesn't work, either on JSBeeb via bbcmicro.co.uk or in BeebEm when downloaded. They all hang....
I am not sure what has gone wrong, but looking at it, it is software protection kicking in.
Does anyone fancy looking at the attached UEF and doing a fresh crack of the tape?
I believe it ends up as just a BASIC program as you can see the word RUN when you load it from tape.
DraculaIsland_B.uef
(9.14 KiB) Downloaded 23 times
Thank you in advance...

Lee.

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lurkio
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Re: Anyone fancy cracking Dracula Island?

Post by lurkio » Sat Sep 21, 2019 7:05 pm

leenew wrote:
Sat Sep 21, 2019 4:57 pm
Does anyone fancy looking at the attached UEF and doing a fresh crack of the tape?
Crude attempt:
:idea:

roganjosh
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Re: Anyone fancy cracking Dracula Island?

Post by roganjosh » Sat Sep 21, 2019 9:35 pm

Here's another one. The BASIC program has been de-mangled and file 'K' adjusted to move it into position.
DraculaIsland.ssd
(34 KiB) Downloaded 15 times

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leenew
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Re: Anyone fancy cracking Dracula Island?

Post by leenew » Sun Sep 22, 2019 10:13 am

Thanks for the efforts boys :D

OK, if I load the DRACULA file, (the clear BASIC program) it still is attempting some dodgy stuff.
If I delete line 10 as the call to &C00 was just protection and has now been RTSd anyway, delete lines 20 and 40 as they are just making sure that you get a BAD PROGRAM if you break, then I think we are left with the normal, unprotected BASIC program that will just 'work' as long as it is low enough in memory.
If you set PAGE to &1300 and CHAIN the fully deprotected version program (DRAC on the attached SSD), it even SAVES/LOADS from disc.
Is it preferable to use this version? or should we keep as much of the protection stuff in place?
I am never sure about this.
One part of mer thinks the best solution is to have the clean program that the author wrote before any shennanigans were added to protect it, and another part of me thinks we should stick as closely as possible to the version released....
If we are NOPping out all the protection checks though, may we just ditch it altogether?
DraculaIsland.ssd
(35 KiB) Downloaded 16 times
Thoughts? :-k

roganjosh
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Re: Anyone fancy cracking Dracula Island?

Post by roganjosh » Sun Sep 22, 2019 11:21 am

My usual preference is, for uncracked programs, to make the operation of the program and loader as clear as possible, within reason. Hence, for personal use, I'd go with the version you've derived from what I posted (leaving K just displaying its title info).

However, I know there are purists out there which is why I left that call to $c00 in place (as you say, 'K' puts an RTS in place) and didn't just do away with K altogether (I even left the calls that K makes intact and worked around them). In essence I purposely left the choice to you.

As I work through the stuff on bbcmicro, doing Master conversions, some more of these may crop up (I've certainly come across another one but didn't make a note of the name) so I can tailor things according to the style you decide on. When doing a Master port from any working version I try to make the loader do as much of the work as possible, veering towards the purist style, and have the program work on both Bs and Masters. If someone then subsequently finds that the B version doesn't work then it probably never worked and wasn't my fault. It also means that it doesn't look too much like I've stepped on the toes of whoever put in the effort of getting it working on a B in the first case.

Alan

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CMcDougall
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Re: Anyone fancy cracking Dracula Island?

Post by CMcDougall » Sun Sep 22, 2019 6:42 pm

as the protected original tape is archived & UEF exists, and has never been a disc
then :
Stuff the CALL&C00 as it just checks "hi am still here, so return"

OR just edit it to 'F4' =REM 8)
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Michael Brown
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Re: Anyone fancy cracking Dracula Island?

Post by Michael Brown » Mon Sep 23, 2019 8:09 am

Hi All,
I am sure the version on my Disc096 works. At least under BeebEm.
The game is downloaded to &E00 and a RTS is put at &C00.
Obviously my version only saves to tape as per original game.

I have only played it briefly, so not sure if it hangs later, unless there is something else going on.

Mick.

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Re: Anyone fancy cracking Dracula Island?

Post by Coeus » Mon Sep 30, 2019 2:47 pm

No-one is forcing a purist to use the de-protected version. As long as the original is archived and the de-protected one is labelled as such so it won't be mistaken for an official release then I don't see a problem.

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vanekp
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Re: Anyone fancy cracking Dracula Island?

Post by vanekp » Tue Oct 01, 2019 7:34 pm

looks like that tape image is also not original as the code seems to be tampered with NOP's and RTS
Just curious now what it did have as copy protection? anyone got an untampered version of this tape?
Peter.

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