I don't know which ROM it is using because it is the old phone of my sister and I flashed the ROM over a year ago. Sorry for that.
But I know that I have CWM Recovery (at least it's something :P )
I am stuck at the white/green HTC logo. I can't get into bootloader/fastbood mode, VOLDOWN + POWER respectively BACK + POWER won't do something different from just pressing the POWER button. I tried it like 50 times now. Is there another way to get into fastboot? This is odd because today it worked one time (with BACK + POWER)