Category : Unprotects for Games and Such
Archive   : AFS.ZIP
Filename : AFS.UNP

Output of file : AFS.UNP contained in archive : AFS.ZIP

Unprotecting Chuck Yeager's Advanced Flight Simulator v1.0
by Ralph and The Computer Pike (22Jun87)

Written by The Computer Pike


1) The ORIGINAL program diskette.
2) A blank FORMATTED diskette.
3) The program DEBUG.COM (found in most MS-DOS packages).


The copy protection for Chuck Yeager's Advanced Flight Simulator (by
Electronic Arts) was very simple, so save the $10 for the unprotected version
offered by Electronic Arts. Tracing was done on the file AFS.EXE using Micro-
soft's Symbolic Debug Utility - SYMDEB.COM (version 3.00). Concentrating on
any disk I/O, it was found that a portion of the program had four identical
groups of two CALLs bunched together. The first CALL routine was CALL 0B31,
which resets the disk, reads the boot record and track 15 (side 0). By the
way, track 15 (side 0) is one of those "hard to copy" tracks. The second
CALL routine was CALL 0B74, which checks the status of the flags set by the
last disk I/O, being CALL 0B31. Replacing these CALLs with NOPs (three NOPs
per CALL), we found that the program ran with no problems whatsoever! It was
that easy! As a matter of fact, we joked about the fact of merely using NOPs
to unprotect the program before running it... It couldn't be that easy! Sure


In copying the program diskette, we decided use COPY *.*. Reasons being
that it allows the COPIED diskette to rid the bad track 15 (side 0). It was
found that using DISKCOPY returned errors and COPYIIPC left track 15 (side 0)
in its "bad" state. So, let's do it this way... If all goes well, you'll only
have to do it once! Perform the following:

1) Assuming that the PC has been booted-up and the DOS prompt
is B>, insert the ORIGINAL program diskette into drive A:
and the blank FORMATTED diskette into drive B:.

2) Type the following after each B> prompt:

md afs
copy/v a:*.*
copy/v a:\afs\*.* b:\afs

3) Now, remove the ORIGINAL program diskette from drive A: and put
it away... You won't be needing it anymore!

4) Insert the diskette containing the DEBUG.COM file into drive A:.

5) You'll have to rename the AFS.EXE file. Type the following at
the B> prompt:

rename \afs\afs.exe

6) Now, enter debug by typing the following at the B> prompt:

a:debug \afs\

7) At each hyphen "-" prompt, type the following:

e de0 90 90 90 90 90 90
e de8 90 90 90 90 90 90
e df1 90 90 90 90 90 90
e df9 90 90 90 90 90 90

8) You'll have to rename AFS.XXX back to its original name. Type
the following:

rename \afs\ afs.exe

9) There! You now have an unprotected copy of Chuck Yeager's
Advanced Flight Simulator by Electronic Arts...


Being an avid user of PC-based flight simulators, I'll have to say
that Chuck Yeager's Advanced Flight Simulator ranks among the BEST! It's a
shame that many of you frowned upon the copy protection... We hope that this
document has aided in removing such a nuisance, and that it will confidently
allow you to use the software freely. Have fun and good luck!!!

Addendum - For single-drive users... And maybe others...

First of all, I'd like to apologize to all you single-drive users. I
don't think you all could have done the above verbatim. So, I went ahead
and COPYIIPC'd (version 3.09) the ORIGINAL program diskette in drive A:.
Ignoring the three errors that track 15 created, I went ahead and used the
copy and performed the unprotection. I ran the copy with no problem. Then,
I DISKCOPY'd (PC-DOS 3.2) the diskette in drive A:. Again, I ignored the
errors. The DISKCOPY'd diskette also ran with no problem. Unless you have
a program that corrects or formats by tracks and sides, you'll have to live
with the errors popping up during copying with no effect to the actual running
of the program. Such a program that allows formatting by track and side is
called ULTRAFMT.COM. It is a public domain program and usually comes as a
package with other ULTRA programs. The programs can be found on most BBSes
under the ARC'd filename ULTRA.ARC. Again, good luck and... sorry!!!

  3 Responses to “Category : Unprotects for Games and Such
Archive   : AFS.ZIP
Filename : AFS.UNP

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: