ZX Classroom - Bypassing BASIC Autostart and MERGE Protection

Bypassing BASIC Autostart and MERGE Protection

ZX Curiosities — BASIC Cracker

Here’s a little help for everyone troubled by BASIC autostart and its protection against MERGE. With the machine-code routine below, you can load any BASIC program so that it doesn’t start afterwards.

You can dismantle the BASIC program, search for and enter POKEs, or do whatever you like. Use the machine-code routine to load only the BASIC part, not any other blocks. The data is loaded into the memory where BASIC should be, so the resulting error will most often reset the computer.

1 FOR n=23313 TO 23366:
  READ a: POKE n,a: NEXT n
2 DATA 221,33,0,64,17

Start the machine-code routine with RANDOMIZE USR 23313 or RANDOMIZE USR XXXXX (the address where you placed this program).