Hello there. I own bp2 since last year. So in order to avoid lags and poor battery performance im gonna write this guide.
So thanks to this i achieved a new phone, without battery drain, a very good battery and cpu temp, and almost root access.
These modifications are made on 3.0.14 ROM, I dont know if this works if your blackphone runs another version.
You can install 3.0.14 here
1. First of all you need to flash TWRP. Download and instructions here
2. Once flashed do not reboot system, type
3. Now it will asks you to allow modifications, NEVER do that, always press "Keep Read Only" because you will get bootloop if you mount system as rw.
More info about that here
4. Now flash magisk, then reboot and install magisk apk. Download from here
NOTE: I dont know why but you need a microsd card in order to flash files, because twrp cant mount /data
NOTE 2: At this point you dont have su BUT you can install magisk modules (yes, xposed too).
Now lets give BP2 Pixel's style.
5. Download this script to remove all Google stuff, yes, just do it. I recommend the EXTREME one.
6. Flash it trough recovery and wipe chache/dalvik. do not reboot yet.
7. Now lets flash Gapps again, updated and modular. Just go to this page and select your desired package. I recommend AROMA not only because you install what you need, but you can remove stock apps (calculator, fmradio, stock email, etc). http://opengapps.org/
8. Now, yes, you can boot system.
9. I also made this script to remove all SilentCircle stuff. Just flash it.
NOTE 3: I wrote this script before removing gapps and that things i explained, so let me know wichs apps still get installed and i will add to the script. Also let me know what apps you want to remove.