Please confirm your iPhone iOS system version is iOS 12.2 (if not, update it to iOS 12.2), 

then use the ONESIM/Blacksim to unlock iPhone.

You can edit iccid according to following methods.

1. Insert the chip and phone sim card together into iPhone,

2. iPhone will show activation screen, 

3. then press Home Button, and select emergency call, dial *5005*7672*88#,

4. input new iccid code, and sending.  

5. Select “Accept”.

6. reboot and activate iPhone, it will have signal and work normally.

You can also use an unlocked iPhone to edit iccid.

Insert the chip and phone sim card together into unlocked iPhone, 

iPhone will show the signal normally.,

Then enter to Settings--Phone--SIM Applications

Select “Edit ICCID”, input iccid code, and sending,

Select “Accept”.

Then insert the chip and sim card into the locked iPhone, 

Activate iPhone, it will have signal and work normaly.

Note:

It can not support CDMA sim card.