Hello Luca I've got two problems.
1. Sometimes invalid SIM detected after boot. Reboot helps, but 3 or 4 times needed.
2. Google play Music streaming reboot the phone. Local playing is all right.
If you need I can send you logcats. I'm on g510.
Congratulation for your built, this is my favorite.
I think it is because CWM search CmUpdate file on sdcard0. (Probably you changed primary SD to external in settings)
Reboot to CWM and try manual udate: install zip from sdcard1/cmupdater folder, than wipe cash and dalvik.