What does crash mean in this case? Did it lock up during the save? Did it save normally and you turned back on to this? Is this fully original hardware including the cartridge?

If so, these old cartridges use batteries/ram for saves and likely won’t work unless the battery has been replaced. Easy enough to do with a beefy soldering iron (big ground planes) and the right parts.

No suggestions on save editors as I haven’t used them, sorry.