The modem does not recognize Korean SIM cards (what?)
#1
I am exploring my newly purchased PinePhone, and I have encountered what looks like quite a big problem for me. I live in Korea, and when I insert a Korean SIM card into the phone, the phone says that the SIM card slot is empty. (Precisely: home screen -> up arrow (all apps) -> settings -> cellular network -> there it says that the SIM slot is empty.)

With any of the other SIM cards I have (I have them from several countries and from different carriers, both expired and working, more than 10 in total), it always says "SIM 0", like the SIM card is there. And when I insert any of the two Korean SIM cards I have (one expired and one working), it says that the SIM slot is empty.

I want to underline that I am not talking about network registration/rejection of my SIM card, I am talking about the modem "locally" reporting the presence of a SIM card, before any network registration. All other phones I have say that the SIM card is there when I insert it, but with the PinePhone I have this issue. I've tried to boot the PinePhone from a microSD card, the same result: sees foreign cards, does not see Korean ones.

I don't know what happens on a deeper level, I don't know if it is actually a hardware issue or a software one, but on the GUI level it looks like this. And this makes the phone almost unusable for me.
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#2
i know that sim cards have features which sometimes make them as incompatible. some cases is informative and some cases physical like voltage.

do you just have bad luck that eg25g thinks that there is no sim in a slot.

i don't know what network standards korea uses, but if sim cards are cdma without lte, then i think it causes some headaches.
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#3
zetabeta,

Well, my SIM card and provider support lte, I see this from the other phone(s) I have. The foreign SIM cards perfectly connect to the network of the same provider where I have my domestic SIM card from.

And again, this is not about network registration, this is about SIM card recognition. The phone says "sim slot empty", not "sim card rejected by the network" or "no networks available" (this is what I would expect if the network frequencies are different).
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#4
i got the point of dead sim cards, because i use them as well (for other devices than pinephone).

i'm just saying that maybe you should try other korean dead sim cards.
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#5
Unfortunately, I don't have any other Korean SIM cards (dead or alive) than just these two.
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#6
I've tried one more Korean SIM card today. Still no success, the phone says that the SIM slot is empty.
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#7
(06-07-2022, 12:51 PM)bdicewk Wrote: I've tried one more Korean SIM card today. Still no success, the phone says that the SIM slot is empty.

i go on vague answer here.

pinephone/eg25-g specifically supports gsm, umts or lte. and sim card need to support one of these, preferably all three.

if sim card supports other technologies without lte, like cdma, evdo, wimax, wipro or something not listed, then i'm pretty sure eg25-g has problems with sim card. however, if sim card supports lte, then it should be shown for eg25-g chip.
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#8
The SIM cards I try definitely support LTE, this is written on them.
Do you have any ideas where and how to investigate further?
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#9
I visited a shop of the phone provider today, and they did something in their system (not with the phone or the sim card), and the sim card started to work (quite buggy though). I cannot be sure if their changes in the system made the phone recognize the sim card, or this is just a concidence, but none of these sounds completely reassuring for me: if this is a coincidence, then I still don't know the real root cause of the problem. And if this is not a coincidence, then this does not look like quite a well design, because the *detection* of the SIM card actually requires some interaction with the network.
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#10
(06-12-2022, 08:20 AM)bdicewk Wrote: I visited a shop of the phone provider today, and they did something in their system (not with the phone or the sim card), and the sim card started to work (quite buggy though). I cannot be sure if their changes in the system made the phone recognize the sim card, or this is just a concidence, but none of these sounds completely reassuring for me: if this is a coincidence, then I still don't know the real root cause of the problem. And if this is not a coincidence, then this does not look like quite a well design, because the *detection* of the SIM card actually requires some interaction with the network.
i also tested dead (no-service) sim card in pinephone. it shows that sim card is connected and also shows 4g symbol for no reason, but no service.

physical dimension of nano-sim and micro-sim are slightly different for thickness. nano-sim is slightly thinner than micro-sim. it might cause some issues, particularly if adapters are used.

good reminder for others:
https://barrelmem.s3.eu-north-1.amazonaw...index.html
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