Let’s look at 3 variants of the situation that lead to the message about an invalid SIM card:
1) The smartphone was originally locked to the operator. And it was unlocked in an unofficial way. After a reset, such a device will be blocked again. The following happened: the smartphone was again in the initial state of binding to the communication provider. In order to solve this problem, it is necessary to determine the “native” operator. This can be found out by knowing the IMEI device. There are various services for determining operator binding using the IMEI code. The unlocking method through contacting Apple support or using the R-SIM adapter will depend on this.
2) The next reason is directly related to the use of R-SIM or Gevey chips in combination with the unlock method through the substitution of ICCID numbers. Some people saw this as a method of cheating customers and began to mount chips from these adapters directly inside the phone, replacing the receiver interface of the SIM card. Such a phone is easily issued for the device without being tied to the operator. A phone with a problematic binding is bought (naturally, it costs much less) a chip is soldered and voila – it is sold as an original for a full price. There are a huge number of these situations in the Russian Federation and most do not know that they were deceived. And they would not know if Apple did not block the popular serial numbers of SIM cards. Smartphones still worked as expected. Until the first reset or OS update of the device. In this case, if you insert another SIM card, the handset will inform you that the SIM card is invalid and iPhone activation does not work.
3) Another option uses software flaws on activation servers. It works as follows: the smartphone is activated using the same R-SIM and if the adapter is removed, the device continued to work as activated until the first reset. From 04/02/2019 through the efforts of Apple, this trick no longer works.
There are recipes for determining a soldered chip in a device.
Insert any other SIM card into the smartphone, then lock the screen and unlock again. The bottom right will be the “i” button. click and find the ICCID – a 20-digit number.
The most popular ICCID numbers (in fact there are hundreds, are given as an example):
If you see them, then a chip is guaranteed to be installed in this device. When you insert the adapter into such a device in the SIM card tray, the smartphone will refuse to work with the SIM card and will not pass activation. If this is the case, then you need to open the device, find it and remove it, restoring the original connection with the contact areal receiver of the SIM card and the filling of the device before installing the R-SIM in the regular SIM card tray.
Here are the cases of soldering in the illustrations: