Care to point us in the direction of the software, as well as instructions on how to do what you did?
Sure,
1stly - My HTC One is S-OFF. Some guides here :
http://www.htc1guru.com/guides/get-s-off/
I am also using the SuperCID :
http://forum.xda-developers.com/showthread.php?t=2317536
I used the decrypted RUU (RUU Zip M7_UL_JB_50_HTC_Europe_1.29.401.16_R_Radio_4A.14.3250.13_10.33.1150.01_release_318486_signed_2_4_decrypted.zip) from :
http://www.htc1guru.com/downloads/ruu-zip-downloads/
Bootloader must be locked, then follow the instructions on the site above :
Instructions:
Download the RUU.zip file and place in your ADB/fastboot folder. I would recommend renaming the zip file to something simple like ruu.zip.
Boot your phone into the bootloader by holding the power and vol up/down buttons at the same time until you see the bootloader screen or if you have your phone booted you can use the ADB command:
adb reboot-bootloader
Now use these fastboot commands:
fastboot oem rebootRUU
Should see the Silver HTC logo. Now issue this command to flash your phone using the ruu.zip file:
fastboot flash zip ruu.zip
Now the first time you issue a command to flash a firmware/ruu in fastboot it only prepares the flash.
You have to issue the exact command again:
fastboot flash zip ruu.zip
The green status bar usually does not reach the 100% mark. When the output in the command window is complete, you can reboot:
fastboot reboot
Once completed you will need to do a few updates until you get to 4.4.2 Sense 5.5

If you use the exact software I mentioned above, you should start off with 4.2. There is probably some RUU with 4.3 - but I didnt really look around for it.