z3c 5803 Lollipop 5.1.1 rooted -> TWRP Factor Reset -> Now Philz Touch 6 instead of TWRP
After the comment above I see on XDA that your device has custom recoveries that can host both TWRP and Phil's I searched my windows PC for the installation file that I flashed to install TWRP. The filename is XZDualRecovery

Google then gave me this link having the manual

This means I have both PhilZ Touch AND TWRP installed.

I solved my problem by the correct key combination during startup:


press VOL-UP for PhilZ Touch;
press VOL-DOWN for TWRP.