As brief as I can be so I don't bore you:
1. Nokia E7-00, recently updated to Anna.
2. Provider is T-Mobile USA, recently changed plans from postpaid to prepaid, using same SIM card that has worked in this mobile for ~1 year without issues.
3. After changing to prepaid, I got an SMS indicating that I was now on prepaid and the transfer is done.
4. Within ~2 hours of receiving this SMS, my phone rebooted (White screen, then boot up, and BEEP-BEEP indicating I have a voicemail waiting).
5. I watched as the phone rebooted many times per day, anywhere from 30 seconds to 2 hours of uptime between reboots.
6. I've hard reset the device, formatted the mass memory, and hard reset again; to no avail.
7. trial and error: eventually I found that the bug seemed to be related to 2G/3G mode switching.
8. If I leave it in Dual Mode, it will reboot after some minutes. If left in EITHER 2G or 3G it will not reboot. I've tried both settings indivisually and get many hours without issue, but in dual mode it will reboot usually after only a few minutes.
9. I have an alternate SIM card (TruSim) that works fine in Dual Mode. On my E7. Note that TruSim actually uses the T-Mobile network in my area (and in both 3G and 2G).
10. I have an alternate mobile device (N900) that accepts the T-Mobile SIM just fine in Dual Mode.
Conclusion:
- Based on points 9 specifically, it seems that there is nothing wrong with the device itself, Dual Mode works fine with another SIM.
- Based on point 10 specifically, it seems there is nothing wrong with my SIM card, it works fine even in dual mode on another device.
- Based on point 2 in combination with 9 and 10, it seems the only logical conclusion is that the new prepaid plan through T- Mobile is behaving differently than the old Post-Paid plan did. But what new behaviour could possibly make the device reboot?!?
Does anyone know of a way to read out an error log from the E7? I was hoping the SIM would fail in the N900 because it is trivial to read out an error log from that device, complete with a recorded reason for the last reboot. But the SIM works flawless in the N900 (worked all weekend with active data connections and switching between geographic areas with only 2G coverage and those with both 2G and 3G coverage).
Anyone here have a clue? Anything I can install on the E7 to log system error events and make it possible to debug?
Note that after formatting the mass memory and then doing a 5-finger salute (hard reset via buttons) the device boots up, I log into my Nokia Account on it, and put it aside: it will reboot in less than 2 hours left untouched and with default settings and apps. This ONLY began after changing the service plan and there were no other events that occured around the same time (phone not dropped or wet, no new applicaitons or firware installed, same sim card, etc).
I'm at a loss here.
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N95-1 ---> N97-NAM ---> N900 ---> E7-00 + N900 (I use them both)
(N95 was pretty good, N97 had potential but utterly failed to deliver, N900 is absurdly good. Those of you wondering, "should I try N900/Maemo/MeeGo"? The answer is a resounding YES)
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