hmm, this Lemmings protection scheme is then quite good. Did you try getting the image with different programs?

Unfortunately changing images is not yet supported, at least not in the way we'D like (mounting more than one bootimage and changing those works, afair). I've complained about this a couple of times already 😀

Prompt has made a patch for image cycling a while ago (http://sourceforge.net/tracker/index.php?func … 551&atid=467234)
Would be really nice indeed if something like this could end up in CVS sometime.. 😀

BTW Ykhwong uses this patch in his builds.

Not related to Lemmings, but how do you make images of floppies that
have weak or bad sectors, or those which use varying sector sizes?
I don't think there's any methodology available besides some custom
hardware to duplicate floppies (not possible for image files).

About lemmings: you can try to boot msdos (diskimage support) where
you can img-mount the floppy. Then full int13 access is available, which
might help here.

I've once seen a very sophisticated copy protection sheme that also checked whether the floppy disk drive was actually working by hooking the FD IRQ (0eh) to find out whether it is being called during int 13h service calls. DOSBox does not imitate this behaviour.
(Note: this isn't fixed by booting into dos suggested by wd).
To figure out whether this might the case for you just look if the program sets its own int 0eh handler.
I've coded a tiny fix for some other application, maybe it works for you aswell. I've included the source incase you feel like experimenting with it (you need TASM for it though).

An interesting mechanism seen in some game: they expected int21/ah=4b
dos exec to use int13 and did encryption for some sectors then.

Hmm your fix didn't work.

I've tried with both rawwrite and winimage. both fails
DosBox output (to the Status Window)

Seek to 0 with type 0 (absolute value 0)
Seek to 0 with type 0 (absolute value 0)
Seek to 512 with type 0 (absolute value 512)
Seek to 34 with type 0 (absolute value 34)

Lemmings starts, asks for performance settings...
Settings chosen

Seek to 0 with type 0 (absolute value 0)
Seek to 0 with type 0 (absolute value 0)
Seek to 80 with type 0 (absolute value 80)
Seek to 80 with type 0 (absolute value 80)

vgalemmi.exe started

Seek to 0 with type 0 (absolute value 0)
Seek to 0 with type 0 (absolute value 0)
Seek to 0 with type 0 (absolute value 0)

Exit to DosBox with "Insert floppy" error.

Can this help you?

I've tried with the original floppy by mount a a:\ -t floppy. That didn't work either. Does dosbox read "boot sectors"? The image has a boot sector named "Key Disk", so I think the hidden shit may be stored there.

Regular mounting doesn't provide int13 services, try the diskimage support.