Why my LG G4 cannot boot or use TWRP custom recovery but cyanogenrecovery without problems?
Finally I got TWRP on my LG G4 h815. The problem was that I had to use the TWRP version of the LG h811 instead of h815. The developers of TWRP put recoveries for the h815 under h811 downloads and recoveries for h811 under downloads for h815.