So I'll just raise my hand here as someone who deals with this day to day:
At least in the US, the DMCA entitles you to make backups of software for your own personal use, so long as no cryptographic security needs breaking to do so. Not an issue for N64 games like is the case here.
The backup of course needs to actually be one YOU made of YOUR COPY of the software. This means buying a cheap cartridge dumper. Look up the sanni cart reader.
So long as you maintain ownership of the original medium, you are entitled to that backup of data. You may not redistribute it, and must delete it should you transfer ownership of the original.
As for romhacks, so long as the romhack itself isn't adding copyrighted data to the game, IE, putting The Simpsons into Mario or something, they're fair game as you're only patching data you are legally entitled to with fan made content. This of course assumes you patch the rom yourself, usually distributed as an IPS file, which is a collection of just the changes to the base ROM, minus the base ROM itself. This has always been legit and is why
romhacking.net has stood unharmed for ages.
Do I think any of this happened? Nope. She 100% just grabbed a pre-patched rom.
But, point is that its not inherently an illegal thing outside of Japan.
