So I've been researching a little. Fortunately pkhex already has starter editing for bw which made my life easier to locate starter in memory link data.
About block 38 decrypting code in BW being commented out: if I recall correctly, I copy pasted code fro B2W2, which were the games I was interested in when I coded the functionality (or more like copied from pkhex). To be more precise, I was interested in entralink forest. Since each encrypted block needs some known data to be decrypted (start, lenght, and seed position) and I did not know where those were for BW the code was left commented. I have now enabled it and seems they used the same structure for BW1 and BW2, so it should work now.
I want to test a little more the memory link feature, I was reported some strange behaviour and want to make sure cheren and bianca team's change when I change the starter pokémon in the edited memory link, afterwards I'll update the app at github.
BTW, doesn't pkhex have support to edit the info in block 38 anyways?
Also, keep in mind that I coded this mainly for myself and there are a bunch of "features" coded in for research purposes. Join Avenue and Medal editting would require more research and work. The other editors should work as intended, but don't expect them to be bug free. I'm not a programmer, everything I have coded has been for fun and self interest, whith a mindset of "making it work". The code is hacky, ugly and poorly documented, and I'm sorry for anyone trying to understand it.
Just use pkhex whenever it's possible. Of course the best route would be to recode everything as pkhex plugins, but I don't have neither the time or skill to do so.
ps: if for some reason you need to decrypt block 38 right now tell me via pm and I'll send some binaries, but it shouldn't take long for me to update on github
EDIT: https://github.com/suloku/BW_tool/releases/tag/20211313_21124
@Jollygator