ECC on Intel NUC is hardware locked.

It’s not going to work. Intel’s 12th-gen consumer CPUs (including the i7 in that NUC) have ECC support physically disabled at the silicon level. No BIOS hack, no firmware mod, no soldering trick will enable it.

The NUC platform itself doesn’t even route the necessary signals for ECC UDIMMs. Even if you forced a server-class chip into a consumer board (which you can’t), the memory controller on that i7 just ignores the extra bits. The “no ECC support” in the spec sheet isn’t a suggestion—it’s a hardware limitation.

If you absolutely need ECC, you need a different platform. Look at an AsRock Rack or Supermicro board with Intel’s W-series (like W680) or AMD’s Ryzen Pro or EPYC. Those actually support ECC UDIMMs because the controllers aren’t fused off.

Stick with non-ECC RAM for that NUC. It’s cheaper, and the NUC will run fine.