How to reproduce:

• save a zero length pico8 file

cstore(0,0,0,"blah.p8")

• reload() file from another cart

reload(0x0,0x0,0x4300,"blah.p8")

surprise! 0x0 -- 0x42ff was been wiped out clean even if "blah.p8" doesn't contain any data :/

this is actually what I would expect to happen... cart ROM is not a variable length; it always contains data in the entire addressable data region. maybe you are thinking of the p8 file as the cart? but to me it is just a text representation of the cart, and anything empty there is actually just 0s at runtime when the cart is loaded

I agree with kittenm4ster. This is to be expected. Roms are all the same size. Technically a .p8 isn't a rom, it's just info on what to put in a rom. The .p8.png is a rom, and it's always the same size. Being able to treat a .p8 as if it were a rom is just a dev convenience, I'd say.