Krack Notes for XPreview 1.0

This Program used to be a demo. It would not open more than 1 document per session. We have removed this limitation and released it as a full working copy. 

How we Kracked it:

We set a trap in TMON for _SysBeep. When XPreview 1.0 beeps to tell you it can’t open more than one document, TMON takes over. As usual we opened an Assembly window anchored to ∆PC. If you hit “POP A6”, it’ll return you to the program and let you hit OK, then break back in where the program returns from the error message routine. One more POP A6 puts you back in right after the JSR that gives you the error. If you scroll up a few lines you see it compares something to “1” and branches past the JSR that gives you the error if it’s less than or equal to 1. Bingo! We want it to always branch past the JSR so we open XPreview 1.0 with Resorcerer, open the CODE 2 resource, scroll to the “opennewdoc” routine at offset $9E. Change the “BLE” to “BRA”.