You do not need to set up any settings for original carrier, everything will work out of the box. If specific carrier is selected it is only guaranteed to work with that specific carrier. The item "New Store Retrn Samsung Galaxy S8+ Plus G955U G955U1 Black GSM Unlocked T-Mobile" is in sale since Monday, March 11, 2019. This item is in the category "Cell Phones & Accessories\Cell Phones & Smartphones".The seller is "cellitems" and is located in Northbrook, Illinois. This item can be shipped to United States, Canada, United Kingdom, Denmark, Romania, Slovakia, Bulgaria, Czech republic, Finland, Hungary, Latvia, Lithuania, Malta, Estonia, Australia, Greece, Portugal, Cyprus, Slovenia, Japan, China, Sweden, South Korea, Taiwan, South africa, Belgium, France, Ireland, Netherlands, Poland, Spain, Italy, Germany, Austria, Bahamas, Israel, Mexico, New Zealand, Singapore, Switzerland, Norway, United arab emirates, Qatar, Kuwait, Bahrain, Croatia, Costa rica, Antigua and barbuda, Aruba, Belize, Dominica, Grenada, Saint kitts and nevis, Saint lucia, Montserrat, Turks and caicos islands, Barbados, Bermuda, Brunei darussalam, Bolivia, French guiana, Guernsey, Gibraltar, Guadeloupe, Iceland, Jersey, Jordan, Cambodia, Cayman islands, Liechtenstein, Sri lanka, Luxembourg, Monaco, Macao, Martinique, Maldives, Oman, Pakistan, Paraguay, Reunion, Uruguay.