I used the 7zip program to extract and did the process twice, which worked, and the update occurred successfully.
I also understood what you expose ... adding the core of DraStic would be more complex then adding the DeSmuME ...
Sorry that unfortunately it really is not working well ... presents extreme slowness in the gameplay. I posted the video of youtube with the operation of DraStic because in the tests, it is perceived that it is doing very well for both simple games (2D) like New Super Mario Bros, both for more complex games like Mario Kart DS, in which both Worked extremely well on Raspberry Pi 3 with the DraStic core ....
If someday you can add this core, I'll be happy to be able to test and report the result ...
Apparently DraStic is a more advanced emulator in terms of Nintendo DS, because even on Android I have it and works very well emulation!