-----------Circus Subtraction---------- A 4am crack 2016-03-01 --------------------------------------- Name: Circus Subtraction Genre: educational Year: 1986 Publisher: The Continental Press Media: single-sided 5.25-inch floppy OS: Diversi-DOS (T02,S02 has the string "C1983 DSR" backwards) Previous cracks: none ~ Chapter 0 In Which Various Automated Tools Fail In Interesting Ways COPYA immediate disk read error Locksmith Fast Disk Backup unable to read any track EDD 4 bit copy (no sync, no count) works Copy ][+ nibble editor modified data epilogue ("BF AA EB" instead of "DE AA EB") Disk Fixer ["O" -> "Input/Output Control"] set Data Epilogue to "BF AA EB" all tracks readable T00 -> looks like a DOS 3.3 RWTS T11 -> DOS 3.3 disk catalog T01,S09 -> startup program is "HELLO" Why didn't COPYA work? modified epilogue bytes (every track) Why didn't Locksmith FDB work? modified epilogue bytes (every track) EDD worked. What does that tell us? no half or quarter tracks almost certainly no nibble check (just structural changes to epilogue) Next steps: 1. capture RWTS with AUTOTRACE 2. convert disk to standard format with Advanced Demuffin 3. patch RWTS to read standard format ~ Chapter 1 In Which We Attempt To Use The Original Disk As A Weapon Against Itself [S6,D1=original disk] [S6,D2=blank disk] [S5,D1=my work disk] ]PR#5 CAPTURING BOOT0 ...reboots slot 6... ...reboots slot 5... SAVING BOOT0 CAPTURING BOOT1 ...reboots slot 6... ...reboots slot 5... SAVING BOOT1 SAVING RWTS SAVING IOB ]BRUN ADVANCED DEMUFFIN 1.5 ["5" to switch to slot 5] ["R" to load a new RWTS module] --> At $B8, load "RWTS" from drive 1 ["6" to switch to slot 6] ["C" to convert disk] --v-- ADVANCED DEMUFFIN 1.5 (C) 1983, 2014 ORIGINAL BY THE STACK UPDATES BY 4AM =======PRESS ANY KEY TO CONTINUE======= TRK:................................... +.5: 0123456789ABCDEF0123456789ABCDEF012 SC0:................................... SC1:................................... SC2:................................... SC3:................................... SC4:................................... SC5:................................... SC6:................................... SC7:................................... SC8:................................... SC9:................................... SCA:................................... SCB:................................... SCC:................................... SCD:................................... SCE:................................... SCF:................................... ======================================= 16SC $00,$00-$22,$0F BY1.0 S6,D1->S6,D2 --^-- ]PR#5 ... ]CATALOG,S6,D2 C1983 DSR^C#254 045 FREE *B 003 CHAIN *A 027 CIRCUS.SUB *T 008 CIRCUS.SUB.LFILE *T 010 CIRCUS.SUB.VFILE *A 015 BEG *T 003 HELLO.LFILE *T 007 HELLO.VFILE *B 011 INTRO *B 017 PW.CHARS *B 033 PW.CS.TI *B 049 PW.SUB.SCREEN.1 *B 050 PW.SUB.SCREEN.2 *B 043 PW.SUB.SCREEN.3 *B 041 PW.SUB.SCREEN.4 *B 044 PW.SUB.SCREEN.5 *B 051 PW.SUB.SCREEN.6 *T 026 PW.SUPPORT *B 005 PW.SUPPORT.OBJ0 *B 002 SPACE.TABLES *B 002 Y/N.CHARS *A 004 HELLO ]RUN HELLO ...works... [S6,D1=demuffin'd copy] ]PR#6 ...grinds... My copy can't read itself yet. This is not unusual. ~ Chapter 2 In Which We Remove All Traces Of Copy Protection Using An Automated Tool That I Wrote For Just Such An Occasion [S6,D1=demuffin'd copy] [S5,D1=my work disk] ]PR#5 ]BRUN PDP T00,S03,$35 change BF to DE T00,S02,$9E change BF to DE Quod erat liberandum. --------------------------------------- A 4am crack No. 625 ------------------EOF------------------