[GUIDE] How to SIM unlock and flash HTC One on Sprint

[NOTE] You will have to be on stock Sprint ROM or base for this to work. This method will also work on phones which have a bad ESN

• Root your device [GUIDE]
• Download Android Terminal Emulator from Google Play Store
• Run Terminal Emulator
• Type "su" (excluding quotation marks) and grant it superuser permission
• Type "am start com.redbend.vdmc/com.htc.omadm.test.TestMainActivity" (excluding quotation marks)
• You should now see a drop-down menu on your device
• In that menu, select "API", then scroll down 'till almost end and select "simlock"
• Reboot the device and it should now accept SIMs from GSM providers.
• Enter *#*#4636#*#* in your dialer
• In the phone information section (the first one) set preferred network type to something that is GSM specific: "WCDMA Preferred", for example. The phone will switch to GSM mode

Here's a video also if you get stuck