8 Gigabyte Sandisk MicroSDHC Incompatibility

[Al Johnson]

On Friday 21 May 2010, Yann Droneaud wrote:
> Le jeudi 20 mai 2010 à 21:06 -0400, Vencabot Teppoo a écrit :
> > Hello, community! This is my first time joining a mailing list, so
> > excuse me if my netiquette leaves anything to be desired, and let me
> > know.
> 
> Hi,
> 
> I have a Kingston SDC4/4GB-2ADP : 4GB SHDC which shows write errors when
> access are not aligned on a boundary. I've first suspect a problem with
> the Freerunner has the problem only arise when booting from this SD
> card.
> But I've tested it latter with a USB card reader (Transcend M5) and
> found problems when random reading/writing on a partition.
> I've retried with 1MB aligned partitions and found that everything was
> going well.
> 
> So aligning partition is not only a matter of performance, for some card
> it's also a requirement.
> 
> To align partition with fdisk from util-linux use the following options:
> 
> c  - toggle msdos compatibility flag
> u  - set unit to sectors instead of cylinder
> 
> See for example:
> http://old.nabble.com/-ANNOUNCE--util-linux-ng-v2.17.1-td27685302.html

Very interesting. I've not seen that mentioned for SD cards before. I have one 
of those that's resisted all other attempts to get it working reliably in a 
Freerunner, but the same partition table is fine when the card is in a usb 
card reader, or the SD slot on my netbook. I'll have to give this a try.