CRC-32 is widely used by emulators (DeSmuME, MelonDS, NO$GBA), ROM management tools (ROMulus, ClrMAME Pro, ROMVault), and no-intro databases to uniquely identify ROM files.
Using a hex editor (HxD), open the .sav file, find the bytes 8a 42 d3 6e at offset 0x3F0 to 0x3F4 , and change them to the official B8 B5 C0 B2 . This tricks the emulator into thinking the save belongs to a clean ROM. pokemon black 2 - 8a42d36e