Other phones can't use SIMs after being placed in Librem 5

Hardware Librem 5
1

I had a weird experience testing SIMs in the Librem 5, and I was wondering if anyone else has seen this happen to them.

I took a SIM from Tigo (a cellular carrier in Bolivia) that I have been using in an AOSP phone (Xiaomi Redmi Note 7 with LineageOS 22.2) for the last 5 years, and I put it in my Librem 5 USA and PinePhone 1.2b to see if it would work in them. It was detected in both the Librem 5 and PinePhone, but didn’t work correctly in either (no calls or data). When I returned the Tigo SIM to the Redmi Note 7, it was no longer detected. Settings > Internet and Network > SIMs in LineageOS was grayed out, meaning that no SIM was found.

Then, I tested a SIM from Entel (another Bolivian carrier) that I have been using for the last month in a Pixel 8 Pro with /e/OS 4.2. This SIM worked well in the Librem 5 (I tested 2G calls, SMS and 4G data). I then tested it in the PinePhone, which was not able to detect the SIM. When I returned the Entel SIM to the Pixel, the SIM card was no longer detected.

I took the Tigo SIM to the Tigo office, and they told me the SIM was bad (not detectable), and gave me a new SIM. The new SIM worked correctly in my Pixel 8 Pro, but when I transferred it to the Librem 5, it didn’t work, and when I put it back in the Pixel 8 Pro, the SIM was dead again. I showed this to the Tigo employees, and they couldn’t explain how this had happened, They gave me another SIM and I decided to stop playing with fire and kept it in the Pixel 8 Pro.

Then I went to the Entel office, and they also told me that the Entel SIM was not detectable, and they gave me a new SIM. I asked them if they could tell me why it didn’t work, but they were remarkably incurious and just chucked the old SIM in the trash.

I suspect that the problem is the BM818-A1 in the Librem 5, and not the EG-25G in the PinePhone, because the Entel SIM was working in the Librem 5, but not detectable by the PinePhone. With the second Tigo SIM that stopped being detected, I never put it in the PinePhone. My BM818-A1 has firmware YCSNO_M100E_1ACD_B325_V1.0.0.2_20220930 and VoLTE is enabled. I’m guessing that the BM818-A1 is writing something to the SIM cards that makes them undetectable when put in other phones.

The crazy thing about this situation is that I have another Entel SIM which works perfectly in the Librem 5, but I have never tried putting that SIM in any other phone, and now I am afraid to try it in another phone after watching 3 other SIMs get destroyed.

Has anyone else seen SIMs stop being detected in other phones after being in the Librem 5?

PS: I should add that I have one of the first Librem 5 USA models, so all this weirdness might be related to any early production build.

2

Are you shutting down (powering off) the Librem 5 before inserting or removing a SIM? It is known to be unsafe to do so while power is applied i.e. may fry the SIM (so that by definition the SIM will then not be usable in any phone, including in the Librem 5 thereafter). You can find discussion of this in this forum.

I’ve done a fair bit of SIM swapping between a set of phones including multiple iPhones and my Librem 5 - and I would always power off both source and destination phone before moving a SIM.

3

I’ve moved SIMs in and out of the Librem 5 to other phones (degoogled Android), and never have had an issue. I, too, make sure to power off before inserting or removing a SIM, in all my phones.

4

I did not power down the Librem 5 before extracting the SIM. However, the Librem 5 automatically turned off when I extracted the SIM tray. I’ve never had a problem extracting the SIM card from other phones without turning the phone off. From what I have read online, modern smartphones generally support hot-swapping, but there is a small risk of data corruption. However, in my case, it does appear that the SIMs were getting permanently damaged, so I’m always going to shut down the Librem 5 in the future when SIM swapping. Another possibility is that it is the Pixel 8 Pro which is frying the SIMs, because it was turned on when I inserted the SIMs.

5

Yes, just as a warning to others regarding the Librem 5 version 1:

The electrical contacts for the Librem 5 and Liberty Phone nano-SIM and microSD tray are not ISO/IEC 7816 compliant. This is due to the type of SIM tray in use. Insertion or removal of the tray while the device is powered on will likely irreparably damage the SIM card. Users should power off the phone before replacing SIM cards.

Board revisions as of approximately mid-2023 include a SMT fuse intended to prevent damage to the SIM card, but this is not a failsafe solution. This issue will be addressed in future hardware revisions.

Source

6

I haven’t seen official advice either way from Apple regarding iPhones but I have seen other advice on the web that you should power down an iPhone before inserting or removing a SIM. It is possible that this advice in respect of the iPhone only applies to very old models while the advice itself has persisted on the web or that the unofficial advice is just bogus (either of which is inclined to be the situation on the web).

However unless you are swapping the SIM more than once a day, shutting down is a small inconvenience when weighed against the potential of frying the SIM, particularly because accessing the SIM tray requires wrestling the case off anyway and locating the tool to eject the SIM tray. :wink:

7

I burned my SIM card one time because I didn’t know to switch off Librem5 before extract it! I suggest you to switch off and wait few seconds (residual electricity inside) before extract it! Moreover, better to leave the battery too! In my opinion Purism had to use this safe circuit!! Save money avoiding important stuff like this it’s stupid!

8

I don’t think this was a cost saving decision. According to the schematics (see p.19), the SIM card is using 1.8V and the microSD card is using 3.3V. The max current for the SIM card is 50mA, and for the microSD it is 200mA. We are talking about two resettable SMT fuses that cost about $0.10 each for an EMS in China. For the Liberty, they would be quite a bit more expensive if Purism sources them at low volume from an American supplier, but still probably less than $0.40 each.

The issue is that designing a smartphone from scratch is damn hard. This is nothing like using a Snapdragon or Dimensity, where Qualcomm or MediaTek provides a reference design. There is no ODM offering reference phone models for the i.MX 8M Quad that Purism could ask them to tweak. Purism had to get a design house to design the Librem 5 from scratch and only a design house which has a lot of experience with phone design doesn’t make these kinds of mistakes. Nicole Faerber stated that Purism went through at least a dozen iterations of the main board, which tells you how hard it is to get this stuff right.

@JCS, I noticed that the posted schematics are still v1.0.6.1 from Nov 13, 2021. Is there any chance that we can get the schematics updated at https://source.puri.sm/Librem5/hw/l5-schematic?

9

The BOM contains this change in this commit dated July 2, 2023:

Manufacturer’s Part Number Designator Description
MF-ASML050/6-2 L79 PTC RESET FUSE 6V 500MA 0402
10

Thanks JC. I see that my component count from the Dogwood schematics for the Librem 5 main board is now off. I counted 1133 components, but this BOM has 1118 components. Do you know if some components for debug were eliminated?

@veleno, In light of what @JCS posted, let me revise that. They are only using one resettable fuse, but they are using a more expensive component than I expected, and it’s from Bourns, which is based in California. Mouser lists it as costing $0.31 each when buying 1000. If they had gone with a Chinese supplier, they could probably get this for cheaper.

11

For the record, as far as I’m aware there have been no schematic or layout changes made since; only minor changes in component placement (BOM).

12

I’ve been using my L5 for 3.5 years now, but had a hiccup a few months ago where I stopped receiving a cell signal. Purism support helped here, but while I waited a week, I moved my SIM back to my old Android phone.

It took some restarts on the Android phone, as well as installing the “Mint Mobile” app and connecting it, but eventually the SIM worked on that phone.

When I did move it back to my L5, it worked with no new issues (granted, I also needed to update my APN settings per Purism).

The way you so casually drop the “version 1” is a bit telling on what may be going on behind the scenes at Purism :slight_smile: . I look forward to good news from you!!