Thread: Kobo SD card problem
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Old 03-16-2011, 08:36 PM   #11
carlb
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Posts: 23
Karma: 200001
Join Date: Feb 2011
Device: BPDN, Kobo wifi
Quote:
Originally Posted by taming View Post
I've used 4 & 8 GB cards without problems from either the Kobo-WiFi or Calibre. It may be a faulty port on the Kobo itself--that has happened to other folks.
I'd tried this with an external 16Gb card (a microSDHC in an SD-card adapter) and received the same sort of disk write error messages described by the original poster. The card was writable without issues if placed in a standard USB SD card reader on a desktop PC.

Oddly, the same 16Gb card, removed from the adapter, loaded with a mirror image of all Kobo wifi firmware partitions on the original 2Gb internal microSD card and installed internally did not display the same issues.

I have not tried 4Gb or 8Gb SDHC cards so don't know if this is an SDHC issue or a matter of larger cards taking more power. I've noticed that the big cards (32Gb as the largest commonly-used size) can actually make the green power LED on my desktop PC's card reader go out on an attempt to insert the card and not come back on until the card is removed. I haven't tried actually measuring how many milliampères are required to feed these beasts, but sometimes a valid 32Gb card will be unreadable or unreliable in a reader which is fine with 16Gb or other SDHC cards.

Another possibility is that you are running newer firmware? I'm on 1.7.4 now.

Quote:
Originally Posted by moffattm View Post
Is it possible the SD cards that are failing aren't properly formatted? From what I've read it is best to use a special format program rather than the one built into Windows.
Most new SDHC cards leave the factory pre-formatted to FAT32 and should not need to be reformatted unless you intend to install some other file system type. I'd expect NTFS is best avoided as Kobo is a Linux-based device, but simply leaving the FAT32 as-is should suffice when using the external SD card slot. (The internal card uses multiple partitions, one FAT32 and the rest Linux-native, but an externally-inserted card is best left as-is).

Quote:
Originally Posted by moffattm View Post
Another possibility is that there are lots of fake SD cards floating around, especially on eBay, even for brand-name cards such as Sandisk.
My 16Gb microSDHC card came from a local bricks-and-mortar compooper store (canadacomputers.com) and is not flotsam or jetsam retrieved from some polluted bay - be it the Bay of Pigs, eBay or even some pirate-infested cove of legend.

The write errors with this card only appear when it is in the external SD card slot on the Kobo. The same microSDHC card and SD adapter work fine on at least two desktop PC's (different readers, different OS'es) so the card itself is good.

I also note that a recent thread on this site had an individual user in Syracuse try external SDHC on Kobo wifi only to see it fail with the same issues; returning the unit to Kobo in North York for replacement fixed nothing.

Something is amiss; I have no idea whether it's hardware or firmware imposing the limitations but using the wi-fi Kobo to write to a 16Gb external SDHC card is failing with disk I/O errors where a 2Gb SD card would work fine.
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