Download the disk image from:

https://archive.org/download/Uncracked4am

The CATALOG of this disk is "encrypted", file names contains a lot of ctrl-H.

Use CiderPress and look at the only significant file "((((((CROSSFIRE-(C) 1981"

0A62-  4C 00 40  JMP  $4000 ; this must be the starting address

Now switch to AppleWin, put a breakpoint at $4000 (BPX 4000), boot and start tracing,
after a while we found:

5927-  20 91 4C  JSR  $4C91 ; this is the copy protection check routine

Now with an hex editor search for $20 $91 $4C, found it at offset $7D27,
change $20 to $2C - BIT.

No Apples II were harmed in the macking of this crack.