- Oct 5, 2015
- 91
- 30
My T-Mobile SIM card broke down and had to be replaced twice in the last three months. There have been other reports, too, that SIM cards from T-mobile tend to fail in Xiaomi devices prematurely, typically after two to eight weeks of use.
This is what I have learned about the problem:
T-mobile SIM cards have a unique function called MEC-Request (Mobile Equipment Change). That function is not implemented in most other providers' SIM cards, but it is part of the GSM specification. When the T-Mobile SIM issues that request, the Xiaomi phone responds with an error.
That's a bug in some Xiaomi phones.
Upon receiving that error, the T-mobile SIM starts running amok. It logs that error condition in its own little flash memory and tries that request again. And again and again, every 30 seconds, day and night. After a few weeks the flash memory in the SIM card can't take any more write requests and fails. The SIM card becomes unusable.
That's a bug in T-Mobile's SIM cards.
The problem was first discovered in conjunction with phones from One Plus, about 2 years ago. Meanwhile, One Plus has developed and distributed a fix.
If you google for the words oneplus T-mobile problem, you will find several reports, for instance, this one:
https://forums.oneplus.net/threads/sim-card-doesnt-work.408276/
Now it turns out that Xiaomi phones (or some of them) have the same incompatibility with T-mobile. I know of Kenzo, Kate, and MI5, but there might be more.
What can you do? You have several options:
1. Dump your Xiaomi and get a Samsung, Sony, Huawei, HTC, or any other brand popular in Europe.
2. Get a replacement SIM from T-mobile once every month.
3. Change the provider. If you love the superb t-mobile net coverage, you can go to one of the T-Mobile affiliates, like, for instance, Congstar in Germany.
You may want to wait for Xiaomi to fix the problem, but they might not even be aware of it. Also, they might not care, because they don't market their products where T-mobile operates.
You may want to wait for T-mobile to fix the problem, but they don't care much for exotic phones. Currently, T-mobile insists it's entirely a problem of the affected phone manufacturers, they should fix their phones.
The truth is, there are two bugs. In both the phone and the SIM card. Fixing one of the two would be sufficient to eliminate the problem.
This is what I have learned about the problem:
T-mobile SIM cards have a unique function called MEC-Request (Mobile Equipment Change). That function is not implemented in most other providers' SIM cards, but it is part of the GSM specification. When the T-Mobile SIM issues that request, the Xiaomi phone responds with an error.
That's a bug in some Xiaomi phones.
Upon receiving that error, the T-mobile SIM starts running amok. It logs that error condition in its own little flash memory and tries that request again. And again and again, every 30 seconds, day and night. After a few weeks the flash memory in the SIM card can't take any more write requests and fails. The SIM card becomes unusable.
That's a bug in T-Mobile's SIM cards.
The problem was first discovered in conjunction with phones from One Plus, about 2 years ago. Meanwhile, One Plus has developed and distributed a fix.
If you google for the words oneplus T-mobile problem, you will find several reports, for instance, this one:
https://forums.oneplus.net/threads/sim-card-doesnt-work.408276/
Now it turns out that Xiaomi phones (or some of them) have the same incompatibility with T-mobile. I know of Kenzo, Kate, and MI5, but there might be more.
What can you do? You have several options:
1. Dump your Xiaomi and get a Samsung, Sony, Huawei, HTC, or any other brand popular in Europe.
2. Get a replacement SIM from T-mobile once every month.
3. Change the provider. If you love the superb t-mobile net coverage, you can go to one of the T-Mobile affiliates, like, for instance, Congstar in Germany.
You may want to wait for Xiaomi to fix the problem, but they might not even be aware of it. Also, they might not care, because they don't market their products where T-mobile operates.
You may want to wait for T-mobile to fix the problem, but they don't care much for exotic phones. Currently, T-mobile insists it's entirely a problem of the affected phone manufacturers, they should fix their phones.
The truth is, there are two bugs. In both the phone and the SIM card. Fixing one of the two would be sufficient to eliminate the problem.
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