OK, I hope this is of help to everyone. Basically, Nokia doesn't care about us and completely denies this problem.
I wrote the following letter to Nokia Customer Service:
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Dear Sir / Madam
I, like many other users of the 3110c have been experiencing an endless restart loop (the screen flashes white and switches off) which happens whenever music files are placed onto the microSD card (SanDisk 1GB).
Scouring the internet I have learned that this is a VERY common problem amongst 3110c users, however, some solutions to the problem have been suggested.
One such solution that has been mooted is the availability of a more recent firmware update (v 6.01) that supersedes version 5.5, which is currently available on your website. Posts on the official Nokia forum say that this update is only available from Nokia care centres however.
Please could you answer the following queries:
1) Is this fault common to all Nokia 3110c's? If so then why was it brought to market?
2) Is there a firmware update that fixes this problem?
3) If there is an update - please could you send it to me, rather than force me to travel to a service centre.
4) Is there any other means of fixing this rebooting problem.
Please do not attempt to feign ignorance of this issue as I think it is now quite infamous. I have always used a Nokia phone (since 1996) and I am otherwise very happy with my phone. I just want to find a way of fixing it!
I look forward to your reply
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This was the reply
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Dear Mr. X,
we thank you for contacting Nokia Care.
1. We are unable to confirm that this error is a common fault to 3100c´s
2. The latest update, which is available in the Internet is version 5.50. Please note that the Nokia Care Point can offer a newest version. Please contact a NCP near by you.
3. Unfortunately we are unable to provide you with an update. You can get am update only from Nokia Care Points or from Nokia Softwareupdate tool. This tool can be downloaded from:
http://europe.nokia.com/softwareupdate4. If the problem will not be solved after Softwareupdate please contact NCP.
For further Question please do not hesistate to contact again.
We are reachable from Monday to Friday between 9:00 and 21:00 o´clock.
Kind regards
Erwin Sabuel
Nokia Service Professional
Nokia Care Team
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So there you have it! Nokia don't give a damn about us and aren't really willing to help... sorry chaps!