Originally Posted by abhishekk89
Thanks Fuzi0719! Appreciate your reply. Now the reason I ask if S-OFF is possible or not is because, T-Mobile will unlock it only if you have their service for 40 odd days. Also, I really don't want to pay for any unlock services (guess being a college student makes me a cheapskate
). So my third option would then be S-OFFing right ? That's why I wanted to make sure all T-Mobile M7's can be S-OFFed (unlike the M8's where only some phones can be S-OFFed using Firewater method).
You're still not understanding the difference between S-OFF and SIM Unlock. Just because your phone gets S-OFF does NOT make it SIM Unlocked. You might be S-OFF but it will still be SIM locked to T-Mobile. SIM Unlocking and S-OFF are completely different things, one does not affect the other. If you want to use the T-Mobile phone on AT&T, it MUST BE SIM Unlocked, whether by T-Mobile or from getting the code from somewhere else. There is no way around that.
If you are not a customer of T-Mobile, but you purchased a T-Mobile phone, they will provide you the unlock code for free as long as the phone is not reported stolen or was sold while still owed money to T-Mobile. T-Mobile will look at the IMEI number and if it is "in the clear", they will give you the unlock code.
EDIT: Just to clarify, even if you S-OFF, change the CID to the AT&T model, and use the AT&T RUU to flash the firmware and system to the AT&T ROM, if you do not get the SIM Unlock code, the phone will still not work with the AT&T SIM. There is no way around that but to get the unlock code from either T-Mobile or another service. I got my unlock code from unlockcode247.com for the huge price of $3.70. If you can't afford to shell out less than $4 for the code, you can't afford a smartphone, especially at the prices AT&T charges for service.
Phone: HTC One Silver 32GB (T-Mobile)
ROM: HTC-T-Mobile stock 4.4.2/Sense 6.0 (rooted/S-OFF/Unlocked bootloader)
Kernel: Kangaroo Kernel v116
Tablet: Nook Tablet 16GB
ROM: CM 11-M8 with Bexus N2 R5.1 kernel