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Cracking Columns

Started by Cyothevile, December 22, 2020, 12:52:56 PM

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Cyothevile

The one thing we all hate is copy protection on these floppy games. I'm looking at this from a preservationist perspective.

Whenever columns is run either on floppy emulator or physical copied floppy it always fails immediately with copy protection screen.

Upon running this game in the wonderful, excellent open source emulator Tsugaru I have discovered the cause for why columns protection kicks in or so I think. It has the "easy" Protection measure with CRC check according to console in Tsugaru where it will check for additional sectors that doesn't exist on a real copy. A copied disk will have these additional sectors and fail CRC ... With copy protection screen coming up. Authentic floppy won't have additional sectors. This is what makes Tsugaru a very good debugging tool and honestly better than UNZ.

I am getting very close to unlocking this and I might try to unlock other floppy games if I can get columns working. I will open this in a disassembler and try to patch this game. I will keep you informed.

Cyothevile

#1
I have unlocked columns in Tsugaru and it plays successfully. Captainys the best programmer for FMT advised me on how to use the best FMT emulator to identify pointer that is in charge of copy protection. So I forced the emulator to patch a no-operation (9090) and keep going pushing me out of infinite loop!

It should also be possible to use it in the same manner for all the protected software. I will provide a more detailed explanation when I post columns here. Is there a way to upload the file directly to NFG website? I am hesitant posting mega link.

I no longer have an FMT PC with physical floppy drive but I will test the patched version in CX20 with gotek and then post it here once I know it works.

Cyothevile

Columns has been unlocked. tested working on Tsugaru the best FM Towns emulator, my Marty with HXC and also Fresh MX with a written floppy.

While running Tsugaru it goes to the copy protection screen immediately as you can see in the image. It does this also when you copy it on a physical disk or use in a floppy emulator on original hardware.
The type of protection in columns is checking for additional sectors. An authentic floppy won't exceed a certain amount of disc sectors but a copied one will.  So the check fails...well  it passes the check and the infinite loop is triggered showing the Pirate screen. The Red box I highlighted in my photo demonstrates the infinite loop. This is why...again..Tsugaru is the best emulator due to the debugging abilities.  It's also possible to change the pointer value to 9090 in the emulator which is what I did and bypassed the protection. So then it was a matter of actually modifying the disk contents.

I opened Visual Studio and changed the EBFE reference with 9090 which in assembly is NOP or No Operation and that did it! I posted to the Towns FB group and a few people were reported using it such as my friend with his MX and other friend with his UX20.  Another group member reported he dragged and dropped the contents of the floppy disk to his hard drive on his Fresh MX into a folder and was able to play the game without a floppy disk! Excellent!

https://drive.google.com/drive/folders/15XH-T7x6Xrh3I11ovo2nbnD-YjEaEG3p


I posted this to google drive...one in HDM format and one in HFE format. Also I attached a compressed HDM copy to the thread

If there are other locked floppy for the FMT with this exact protection it would take maybe 10-15 minutes to change.  I know Brandish and Dinosaur have some nasty protection measures that are hidden throughout gameplay and crash on you later in the game. This might require investigating.  If someone would be kind enough to give me a by-name list for all these locked floppies...in the name of preservation I will do my best to unlock them.

opooly

Hi,

I m new in this FMT world so I m facing all these issues you saw 4 years ago I guess.

PSU no longer working, as well as CD-ROM drive and even when you are happy to write a floppy game you have the copy protection!

So just a word, thank you for what you done from a preservation perspective, that s really great!