There is a command, I forget what it's called, to get the address pointer of the start of the incbin'd data. I don't see why you couldn't then use that to modify the data, it should work at runtime. You'd just want to be sure that the CPU cache is flushed before reading it back, I've no idea if that is handled automatically or not.
It's a pity that incbin'ing data which then needs to be unpacked in some way, like an image, requires more memory - memory for the original file and memory for the unpacked version (e.g. image data).
It's a pity that incbin'ing data which then needs to be unpacked in some way, like an image, requires more memory - memory for the original file and memory for the unpacked version (e.g. image data).