First of all.. thanks for all the steps.. I did the entire procedure twice and it seems it is working fine, PKHex is able to open the savegame.
Other than that: great work to all savegame hackers, you guys are truly amazing folks!
So I can confirm this works!
To be very frank. Datel used to support the homebrew community on the Gamecube and such by creating homebrew loaders using SD card adapters.. in their hearts I imagine many of the folks there would probably love to help us but after the Diancie debacle where they had to remove everything else unreleased (Latiosnite and such) - I imagine they decided to tighten up things on their side to ensure they can continue selling their adapters - and that included securing their structures. In the end: Datel is a company, they want to make money: if people were to buy PowerSaves adapters to hack their games, while this wouldn't harm their business model, it would certainly harm their model if Nintendo strikes against them for DMCA stuff.