Success in manually installing Android 4.3 OTA update!
This is for my HTC One international phone (originally AT&T phone but I changed the CID and modelid to:
(bootloader) modelid: PN0710000
(bootloader) cidnum: HTC__001
The steps I followed:
1. Download the OTA update ZIP to my Windows PC: Do a Google search: International HTC One gets OTA update to 3.62.401.1
2. Connect my HTC to my PC and drag and drop the zip file there.
3. Boot to recovery, either from the PC command line (adb reboot bootloader) or with button combinations on the phone.
4. Select recovery
5. Wait until you get the picture of the battery with the red triangle inside
6. Press Power, Up volume, and down volume a number of times until it goes to the actual recovery mode. (very very tiny font)
7. Select "apply from phone storage"
8. Navigate to the "0" directory. It should say /data/media/0
9. Select the zip file that you copied from the PC.
10. Do the install, should take 10 minutes.
11. tell it to reboot
12. If it brings you back to that dark screen with the batter icon, reboot again (press power + up volume)
13. It will then reboot regularly, and say "Android is upgrading... optimizing app xxx of 126."
Thanks for all the help from the forum. Now I don't have to wait until HTC pushes out the OTA to my phone.