Edit: "AND you reset the Tampered flag"!!!
... This is not a Rom issue. A tool is available on the HTC One forum that works on our device as well.
Edit: Please note that Roms that are Ported from other devices that do not have a fingerprint scanner might not have all the needed software for the fingerprint scanner on the One Max to work regardless of boot loader being on and tampered flag fixed!
[TOOL] Lock/Unlock Bootloader + Remove Tampered | Aroma GUI
I have personally tested this on my Verizon HTC One Max running a different Rom then stock (ViperMAX) and personally confirm it works.
I take no credit for this Tool.. just sharing the link and info.
Feel free to share One Max experience in this forum.
And don't forget to thank "Chusholot" when visiting the link above to download the Tool.
Current Device : HTC One MAX / Retired HTC Devices: DNA, Rezound, Thunderbolt, Incredible, Eris