gomaemo | # 21 | 2011-04-07, 21:11 | Report

Somehow, I am convinced this is related to the battery. I know it sounds weird, but whenever i change to another battery, the issue either shows up or disappears, for a while at least. For example, when i swapped my extended battery to the OEM one, the issue went away, for a while..

radiosw | # 22 | 2011-04-07, 22:07 | Report

Recieved mine back from Nokia Care today after a week (so missed it) and they replaced the 'board'. So far works ok and sim is recognised and that message has not returned.

gomaemo | # 23 | 2011-04-08, 05:45 | Report

Some new updates: the phone has started to do it more often (Honestly, I do have warranty on the phone, but I just really want to investigate some more, if somebody can help me, so we can figure out this annoying issue). I was wondering if somebody can guide me in the right direction to maybe "reset" the gsm antenna or something of that sort, so that the phone can get signal again (by re-reading the SIM). Maybe refresh the SIM_SECURE partition or something? I am not sure, hope somebody can help. Thanks

shadowjk | # 24 | 2011-04-09, 10:35 | Report

In my case, it worked fine when I did not apply any pressure to the keyboard, or same area on the back. As soon as some pressure was applied, the crossed out sim icon appeared.

Also check output of 'dmesg' after sim icon gets crossed out.

Texrat: My own suspicion was that the battery pushes against the PCB, and/or in combination with heat makes the cellmo side of the phone progressively less reliable.

gomaemo | # 25 | 2011-04-10, 23:29 | Report

Update: Well, today it went from bad to worse. The no SIM icon would NOT go away But, I activated a new SIM card (even though mine is 2 weeks old), but this time, an "older" SIM card. One where the data partition looks like an oval, not a rectangle (t-mobile). The phone is back to working 100 percent (so far) and im crossing my finger that this was the problem, as it was mentioned on other threads. Please let me know if anybody can second this.

geneven | # 26 | 2011-04-11, 00:36 | Report

To me, this points not to the battery but to the particular hardware jiggling that changing the battery creates. The culprit might be near the battery, though whether it can be found is another question.

sjgadsby | # 27 | 2011-04-11, 01:45 | Report

A memory leak would be consistently--though admittedly only temporarily--cured by a reboot. Is that what people are seeing? The descriptions posted here make me think people find themselves confronting a problem not so easily worked around.

It would fit with geneven not running across the problem though. He'd be resetting the clock on the memory leak every time he swaps batteries.

In contrast though, I reboot less often than once a month, and I haven't had my N900 forget it has a SIM. Of course, I also make or receive a call on my N900 less often than once a month, so if there's a memory leak caused calling, I'm unlikely to see it.

That's a whole lot of every which way. Are people finding that rebooting (or perhaps even power off + pulling the battery) always fixes the problem, at least temporarily?

gomaemo | # 28 | 2011-04-11, 03:28 | Report

Thank you for this. Well with me, a reboot would fix it about 30 percent of the times (so really non consistent). As days go by, the issue gets worse, more reboots are needed, to finally get it to recognize the SIM/ get signal. Now after a few days (like today), the phone will just refuse to recognize the SIM. Like I said today I swapped SIMS (I put it an older type of SIM instead of the new type), and so far, it has not done it once. Here is whats also strange: When it starts doing it, it would just not display any bars, and once you open the keyboard, the no SIM symbol appears, close keyboard, no signal, open keyboard..... So when I noticed that I was convinced it is being caused by a hardware tweak. But then again, it should be consistent! Once I changed batteries, the issue didnt appear until a few weeks later, during which I was convinced the battery is causing it. Now the SIM seems to do it. So my conclusion: is there some sort of a "Hardware ID" that once changed, the phone does not accept any SIM? This would be the only thing that sums all these things up. Can you think of anything else?

sjgadsby | # 29 | 2011-04-11, 04:00 | Report

Okay, so it sounds as though it's not a memory leak in Maemo. A reboot would cure that.

A loose cable that runs between the display and keyboard sections of the N900, perhaps?

This might support Texrat's memory leak theory. Rebooting (or shutting down and restarting) an N900 completely restarts Maemo, thereby correcting the damaged caused by any memory leaks there. However, I don't know whether or not a reboot also causes the GSM processor to restart.

It could be that the GSM processor maintains its state through a phone reboot. Pulling the battery, either to replace the battery itself or the SIM card, would force the GSM processor to start anew though.

Does pulling the battery get your phone working again (at least temporarily) every time? There's a small backup battery or capacitor inside N900s to help them retain settings (such as date and time) through battery changes, so you may need to keep the battery out of your N900 long enough for that to drain. A minute or two should be more than enough.

gomaemo | # 30 | 2011-04-11, 04:33 | Report

The answer to your question is No. Today in the morning, I literally pulled the battery out and restarted the phone about 30 times, to no avail: the no SIM symbol would just not leave ( During rebooting I also was taking the SIM out and putting it back in ). When I activated that new SIM, and I rebooted using it, the phone has (still) been perfect, even when I open the keyboard, even if I restart. But I bet that in a few weeks, I am going to start seeing it (about once a week), and then it will dramatically increase.