[U-Boot] Request for Help: How to save data to an SD/MMC card

[Graeme Russ]

Hi Ilya,

On Wed, Dec 14, 2011 at 10:46 AM, Ilya Yanok <yanok at emcraft.com> wrote:
> Hi Graeme,
>
> On 14.12.2011 03:37, Graeme Russ wrote:
>>> Well, it shouldn't be that hard to get the data written to specific
>>> blocks on the dev PC using dd command.
>>
>> But what about bad blocks?
>
> You don't need to worry much about this. MMC/SD card are not a raw flash
> devices they contain FTL that handles this internally. See
> http://www.linux-mtd.infradead.org/doc/ubifs.html#L_raw_vs_ftl
> for details.
>
> That's why you can use generic filesystems on MMC/SD (neither FAT not
> EXT2/3/4 is not designed for raw flash).

Thanks, that is good to know - I'll try this out when I get a chance

Nonetheless, I think it will be advantageous to have filesystem write
support in U-Boot anyway to allow seamless transfer of data between
development mchines, U-Boot and the target OS.

Regards,

Graeme