To understand the fix, you must first understand the hardware. The Nintendo DSi was a mid-generation upgrade over the original DS. It featured more RAM, faster CPUs, and a camera. To utilize this, Nintendo introduced the "DSi Enhanced" standard.
It is important to note that this is not a "crack" in the traditional sense. It is a repair of the cryptographic signatures. When a release group or patcher says the binaries are fixed, they mean the ROM now contains valid signatures that the DSi bootloader recognizes. pokemon black 2 dsi binaries fixed