usata allows you to remove the optical drive from your Wii U and replace it with a hard drive or solid-state drive. Combined with MLC rebuilding tech you can have up to 2TB of fast, internal storage. The drive also shows up and is usable in linux-wiiu.
Your drive must stay within the power limits of the original optical drive - 1.8A@12V, 1A@5V. 3.3V is not connected to maximise compatibility with drives using PWDIS. Since I'm not an expert electrical engineer, the board might not be capable of carrying full power - I would stick to laptop drives or SSDs rather than full-sized spinning disks. If you know how to check the current capacity of the board, please let me know if it's up to scratch!
I have successfully gotten boards made by PCBWay and JLCPCB in the past. The parts used are the TE Connectivity 2023246-2 and the Hirose FH28K-28S-0.5SH.
You're welcome to make this board, sell it, and remix it as allowed under the license - gerbers are available in the releases section. If you're leaving my name and URL on it, please make sure the version number on the board matches a release.
I'm no expert in PCB design or assembly but I tried my best here. Feel free to file an issue with your thoughts or file a pull request with your improvements.
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Note that I am happy to accept attribution on a website, git repo, forum post, documentation etc. rather than on the derivative board itself.