Hi All,

I bought my N800 over the December period in the US, but I'm located in Singapore – i.e. My Nokia warranty does not cover the device in Singapore. Since I got the device I have not been able to write to a number of SD cards that I have tested, and I'm experiencing almost identical symptoms to http://www.internettablettalk.com/fo...ad.php?t=12607.

Here are the things I'm experiencing:

1.If I copy data from the device to the internal (or external) SD card (my cards or the test ones provided by Nokia Singapore) memory via the file manager it appears to have copied... but I'm unable to open the copied data, as the device reports the data as corrupt. Furthermore if I reboot the device the data is gone.

Within the Terminal, if I issue the dmesg command and look around a bit I find a lot of errors relating to the mmc device. Here is a short extract:

2.The above symptom seems to break of lot of functionality on the device:
>Application manager often is unable to install applications, and the log entry indicates a problem writing to the SD card:

>The Mapping application crashes when opening, I believe this due to the app being unable to cache to the SD card (/dev/mmcblk0p1).

>I'm unable to create virtual memory (swap) via the control panel applet. It just hangs.

3.Now here is the interesting part. At the Nokia Care store I tested a 64mb MMC card provided by them, and it worked!. I reconfirmed this with a colleagues 64mb MMC card.

What I tried to fix the problem:

1.Reflashed the N800 a number of times with both the latest versions of OS2007 (RX-34_2007SE_4.2007.38-2_PR_COMBINED_MR0_ARM.bin ) & OS2008 (RX-34_2008SE_2.2007.50-2_PR_COMBINED_MR0_ARM.bin)

2.sfdisk'ed and reformatted both my SD cards. I have the Nokia 128mb miniSD (in adapter) which shipped with the device, and a Kingston 2gb SD card.

3.Taken to Nokia Singapore to repair out of warranty (at a cost). But basically they had no clue, and stated that if I wanted to fix it it there would be a flat fee of SGD250.00 (Approx 180 US dollars).

So based on the above I have made the following conclusion...

SD is not working on my N800, but MMC is.

My questions to the community:

1.Any ideas why SD is not working, and MMC is?
2.What are the fundamental differences between SD and MMC? Is this possible that it is a voltage/clock speed issue?
3.If 64mb MMC card works, does that mean that that a 2gb MMC card will also work?
4.Is it possible to work around this problem with software? For example a kernel patch from someone like http://intr.overt.org/blog/?p=44.

Thanks.

Bumping, to get fresh eyes on this problem.

The easiest test would be try other cards before heading for repair.


bun

Thanks Bunanson, however I have tried a number of SD and MiniSD (in adapters) and I still experience the problems I mentioned in my original post.

I have tested two 64mb MMC cards, and with them all my problems disappear. This is what lead me to ask the internettablettalk community the following questions:

Thanks.

I had similar issues with a micro-sd card (which worked great in my phone and via an sd usb adapter on my desktop). Specifically, after writing a couple hundred meg, the card would start throwing kernel errors. What I did to fix it was:
1) Plug the card into my desktop
2) used "dd" to overwrite the first couple kbytes of the card (so that there was no partition information on it)
3) stuck it back in the nokia, and used the format option on the file manager, which re-layed down the partition table and filesystem.

A second thing I did was to format it from my desktop with a full verify (mkdosfs -c). This I did by keeping the card in the nokia, and hooking the nokia to the computer via usb.

Thing is, I don't remember which order I did this in, so I'm not sure which one ended up working.

Thanks derekp.

I will try your suggestions, however I think it is unlikely to solve the problem as I have tried multiple SD cards, including ones that are working fine in a colleagues N800... and no luck.

I will post my results.

Oh, one more thing. One reason why mmc works more reliably than sd in your device is mmc uses only 1 pin to transfer data, where sd uses 4 pins (i think). So it could be that your device has contaminated (or oxidized) contact pins in the sd slot. In fact, now that I think about it, a Sharp Zaurus that I had would have the same symptoms with SD cards (never tried mmc cards in it though). If I moistened the contacts before inserting the card, it would work (for a while). The way I ended up fixing it was to apply some switch grease to the contacts on the card, then it worked reliably 100% of the time. (Make sure to use a lubercant that is made specifically for electrical contacts -- you should be able to find it at most electronic stores).

Thanks derekp... I'll give that a try.. however once again I am doubtful that this will solve the problem as I am experiencing the same issues regardless of which SD slot I use on my N800.

If the problem is related to the 1pin vs. 4pins - and seeing that I'm having the problem in both slots... this would indicate that perhaps there is a common point of failure which is causing the issue on both slots.

Thanks for your input so far.

Hi All,

Well, the problem has been solved by getting Nokia US to give me a new unit. I think my N800 has now done more international travel in it's short life, than I will achieve in mine.

Glad to be a productive N800 user once again.

Cheers.