Thread: N800: SD does not save data, but MMC works
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db0yd13 is offline db0yd13
2008-01-12 , 02:31
Posts: 9 | Thanked: 0 times | Joined on Jan 2008
#1
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:

Code:
mmcblk0: error 1 sending read/write command
end_request: I/O error, dev mmcblk0, sector 1016
FAT: Directory bread (block 919) failed
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:

Code:
E: Could not open lock file /media/mmc2/.apt-archive-cache/lock - open (5 input/output error)
W: Unable to lock the download directory, but cleaning it anyway.
>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.
Last edited by db0yd13; 2008-01-12 at 03:25.