Step 1: Root the HTC One S.
Step 2: Download unlock.zip [Dropbox]. Extract its contents using a suitable software.
Step 3: Place unlock.sh in /system folder on your HTC One S using a root-enabled file explorer such as File Expert [Google Play].
Step 4: Now, execute .sh or use Android Terminal Emulator [Google Play] to type in the following commands:
su
/system/unlock.sh
Step 5: You should now see a SIM unlock code on your display. If not, open up /sdcard/sim_unlock_code.txt to get it from there.
Step 6: Shut down your device. Remove your SIM card and replace it with a SIM card of an unsupported network.
Step 7: You will be asked to enter SIM unlock code, so type in the code you saw in Step 5.
If all the steps were done correctly the phone should now be unlocked.
