Now that took long, 
a 12hr hackathon from 4 to 4 at morning, just to switch off the security at a friends HTC One M7, including rooting, SuperCID, MainVer fix, tamper fix and custom recovery! In the meantime I sometimes thought I bricked it and it didnt responded, but now 12hrs later, I got it!!! Also learned a SH!TLOAD of stuff on the way, including usb trace, adb shell fun, phone states, boot order, partition layout, linux commands in general and damn im reliefed I didnt bricked this (before fully working stock) 700 bucks phone, which isnt even mine!^^

HBOOT: 1.54.0000
MainVer before: 2.24.111.3
CID before: T-MOB01

greetz WV