Originally Posted by Ark1406
I'd go with the option of you sending in your phone first. If they send you one first and find ANY trace of your phone being tampered with, they'll charge you $175 no questions asked. My friend sent in the phone first, followed that guide, and they still found a trace (maybe he did it wrong). Regardless, they gave him the option of either paying $300 for repair (includes the $175 tampered charge) or they send it back to him. And he sent it In for the same reason as you. I'd send it in first considering the tamper charger is almost as much as a 2-year contract price
The HTC UK team told me that they will check the phone for tampering, and if something is found, I will get charged £23 before starting repairs and be given the chance to continue repair on my own cost, or return the phone as is.
I have just checked the HTC tracking system, and I can now see my phone as "In repair" status, so I am assuming all's fine.
The guide is for International versions and my phone is Three UK, so the steps are not exactly the same. However, the idea is the same, flash/restore stock rom, make sure supersu is installed, remove Tempered and Unlocked flags, flash stock recovery and then restart the phone loads of times, boot to bootloader and all that to make sure all the flags stick.
Current: HTC One M8 (Gunmetal) + Spigen Slim Armor (Gunmetal)
ViperOne - ElementalX - Firewater S-Off(ed)
Old: HTC One * Galaxy S4 (I9505) * Galaxy S3 (I9300) * Galaxy S3 LTE (I9305) * Galaxy S (I9000)