[meta-freescale] [meta-fsl-arm][PATCH] image_types_fsl.bbclass: Use FAT 32 for images larger than 512MB

[Tzu-Jung Lee]

On Fri, Oct 16, 2015 at 10:18 AM, Otavio Salvador
<otavio.salvador at ossystems.com.br> wrote:
> On Thu, Oct 15, 2015 at 8:27 PM, Tzu-Jung Lee <roylee17 at gmail.com> wrote:
>> Refers to the following commit of poky for more detail.
>>
>> commit 722430a488f39bf583e4a557a254fb84fae4d0a7
>> Author: Darren Hart <dvhart at linux.intel.com>
>> Date:   Wed Dec 12 14:39:15 2012 -0800
>>
>>     bootimg: Use FAT 32 for images larger than 512MB
>>
>>         Fixes [YOCTO #2138]
>>
>> Signed-off-by: Tzu-Jung Lee <roylee17 at currantlabs.com>
>
> I am not against the change however I am curious why we cannot use FAT
> 32 for everything?
>

FAT32 spec requires at least 65525 sectors, which will be around 32MB
with 512-byte sectors.
Images like core-image-minimal, or other reduced image is too small for that.
Some systems (e.x. OS X) reject to mount the image (dd'ed disk) if it
doesn't comply the spec.

Upstream tried to solve it by letting the mkfs.vfat itself to decide
which of FAT16/32 is appropriate for the image.
But it failed to use FAT32 for some larger images. So the solution was
to manually decide which FSTYPE.

Roy

> --
> Otavio Salvador                             O.S. Systems
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