Contents of the F15UNP.TXT file
SOFTWARE PIRATES INC.
F-15 Strike Eagle Unprotect
This file will tell you how to unprotection F-15 Strike Eagle by Micro
Prose. To complete this unprotection you will need the following:
1. A good copy program like BACKUP.EXE or COPYIIPC.EXE.
2. DEBUG.COM can be found on your DOS disk.
3. U-FORMAT.EXE can be found on most Bulletin Boards.
BACKGROUND: The copy protection scheme used by Micro Prose on F-15 Strike Eagle
is very good. I have found no commercial copy program that can make a
usable backup copy of this disk. The F-15 master disk has track 10
specially made. Track 10 has 16 sector ids on it instead of the normal
8 or 9. Using COPYIIPC, track 10 will be reproduced with only 10 ids on
it. When F-15 boots up it verifies, in two places, that all 16 sector
ids exists. The sectors on track 10 contain no usable data. F-15 just
makes sure that they exists. Knowing this we can go in and patch F-15
so that it doesn't check track 10 at all. After patching the program
we can go in and re-format track 10 to normal sector size. With this
done, you will have a working copy of F-15 Strike Eagle that can be
copied by DISKCOPY.COM.
Step 1: Make a backup copy of your master F-15 Strike Eagle disk. Your copy
program must be able to handle non-DOS sector sizes. Norell BACKUP or
Central Point COPYIIPC can do this. Remember to copy both sides of
the disk, F-15 is double-sided. Once you have copied the master
disk put it away. You will not be needing it again.
NOTE: The backup copy just made will not function ... yet. When you are done
with Step 2, the disk will run. When you are done with Step 3, the
disk will be DISKCOPYable.
Step 2: Load DEBUG into memory. Put F-15 backup copy into drive A. From the
DEBUG prompt '-', enter the following:
-L 0 0 36 1
This command will load the 7th sector on track 3 side 0 into memory.
At this point we want to patch the two locations that check track 10
for 16 sector ids. To do this type the following:
-E 0AB E9 11 10 90 *** (MODIFIED ADDRESS)
-E 123 E9 11 10 90
Now we want to write the changes back to disk. To do this type the
-W 0 0 36 1
At this point your backup disk will now function!
Step 3: Now we want to re-format track 10 to normal double-sided track.
U-FORMAT.EXE will do this job quite well. You want to format track
10 with 8 sectors on 2 sides.
Having completed the above 3 steps, you will have a working copy of
F-15 Strike Eagle the can be copied by DISKCOPY.COM.
Use diskcopy to make a copy of F-15 (I know DOS 3.1 works without
aborting but I'm not sure about anything lower) then run F15UNP.COM.
When the disk is diskcopied track 10 is fixed and F15UNP.COM simply
makes the modifications outlined in step 2. It's that simple!!