[AT&T HTC One (M7)] abs0lut3z33r0:
i am in a similar situation , i have 4.1.2 unlocked non rooted htc one at&t .

i think this is the process posted by clsa

How to Update HTC One AT & T android 4.4.2

1. Locked bootloader . http://www.htcdev.com/bootloader
Video tutorial: http://www.youtube.com/watch?v=33UDfztt2No

2 . Install the ROM RUU M7 UL JB43 SENSE50 MR Cingular U.S. 3.17.502.3 Radio 4A.19.3263.13 10.38j.1157.04 Release 334235 Signed 2.exe

Download: http://www.htc1guru.com/dld/ruu_m7_u..._signed_2-exe/

Video tutorial: http://www.youtube.com/watch?v=rpA71FXddyU

This one if your s-off
http://www.htc1guru.com/dld/ruu-zip-...decrypted-zip/
More information: http://xdaforums.com/show...24177228566259

3 . After installing the ROM RUU, unlock bootloader: http://www.htcdev.com/bootloader

4.Install Recovery.
4.1 One HTC CWM Recovery Installer - Touch edition : ! https://mega.co.nz/ # p80QHT6D aSM6r0Ean - 8NDmIhrWnbv2DP0kF_Av3MMs0PC_gsHmE
HTC One CWM Recovery Installer - Non -touch edition : https://mega.co.nz/ # 4wMDzB7a IHEDmEpS4gVJkBmNt5YoPWjtQEduieLoB9N5a_Gyf14 !
renames the file to recovery.img to get simpler .
4.2 With the unit off, press " volume down and power " and put the phone into fastboot mode. ( Disable fast boot )
Copy the image to the fastboot folder : http://www.4shared.com/photo/xsfKLqQ...y_htc_one.html ?
Shift + right button and click "Open command window here "
Enter the commands :
fastboot flash recovery recover.img
fastboot erase cache
fastboot reboot- bootloader

5 . ROOT
Place in recovery mode and flash zip :
http://downloadandroidrom.com/file/t...erSU-v1.65.zip

6 . S- OOF
Video tutorial: http://www.youtube.com/watch?v=NeFwsqU4YL4
rumrunner s -off : http://rumrunner.us/downloads-2/
I tried twice and it worked.
Try several times , it works.

7 . Flash recovery in Stock > Recovery_Cingular_US_3.17.502.3.img >>> http://dh.st/6bH
Copy the image to the fastboot folder : http://www.4shared.com/photo/xsfKLqQ...y_htc_one.html ?
Shift + right button and click "Open command window here "
fastboot flash recovery Recovery_Cingular_US_3.17.502.3.img
fastboot erase cache
fastboot reboot- bootloader

8 . Download AT&T 4.4.2 OTAPkg.zip >>> http://www.androidfilehost.com/?fid=23329332407573841
Boot to the bootloader and choose recovery
Wait a second and press vol up and power for 4 seconds
Wait for menu
Apply "wipe cache patition "
then choose to install from phone storage
Now your ready to flash the ota.zip

And ready .

9. ROOT HTC ONE AT&T 4.4.2
Instalar Recovery.
One HTC CWM Recovery Installer - Touch edition : ! https://mega.co.nz/ # p80QHT6D aSM6r0Ean - 8NDmIhrWnbv2DP0kF_Av3MMs0PC_gsHmE
HTC One CWM Recovery Installer - Non -touch edition : https://mega.co.nz/ # 4wMDzB7a IHEDmEpS4gVJkBmNt5YoPWjtQEduieLoB9N5a_Gyf14 !
renames the file to recovery.img to get simpler .
With the unit off, press " volume down and power " and put the phone into fastboot mode. ( Disable fast boot )
Copy the image to the fastboot folder : http://www.4shared.com/photo/xsfKLqQ...y_htc_one.html ?
Shift + right button and click "Open command window here "
Enter the commands :
fastboot flash recovery recover.img
fastboot erase cache
fastboot reboot- bootloader

Place in recovery mode and flash zip:http://download.chainfire.eu/382/Sup...erSU-v1.93.zip

10. Google Experience Android 4.4 KitKat Launcher on HTC One
Google Launcher: http://d-h.st/7p1

Correct me if i am wrong , there is no RUU posted by HTC hence we follow this process , in case of HTC one x htc posted an RUU

Does Step 2 wipes of the data ? ,