This patch hijacks the death routine to not activate it when a certain flag is set to 1. Open the asm file to see which freeram address is used, and change it if it's already used by some other resource.
When the flag is set to 1, death will be completely disabled, but Mario can still get hurt if big or on Yoshi. Also, falling in a pit will result in an upwards speed boost rather than death.
Note that this won't work if some custom sprite embeds a custom death routine in their code.
Works correctly. Do note that player can get stuck inside of screen boundary if pushed in with a autoscroller, since crushing doesn't kill player anymore. I don't think it's easy to fix with patches, so just don't make your level with death disabled a autoscroller level (like ASMT did).