Hey...not trying to hijack your post but I think we are in the same boat.
I posted following in the AT&T HTC One forum and posting it here as well, hoping to get some answer.
My phone is at:
Android ver 4.4.2
Software ver ARHD 71.1 (ROM ver# 5.11.401.10)
HTC SDK API 6.20
Baseband ver 4T.24.3218.09_10.26.1718.01L
S-ON (Unlocked via HTCDev)
HBOOT - 1.56
How do I update my firmware to v5.12.502.2 with S-ON ? Is there a zip file that I can flash ?
Thank you in advance...