Re: RFC : mmc : boot partition is set as a read-write.

Chris Ball
2011-09-19T03:32:54Z

Hi,

On Sun, Sep 18 2011, NamJae Jeon wrote:
> mmc : boot partition is set as a read-write.
>
> There is a case that user directly update boot partition through mmcblk0boot0,1.
> However, the current boot partition is set as a read-only.
> I suggest that boot partition is set as a read-write if there is no
> reason that it should be read-only.

There is a reason.

Documentation/mmc/mmc-dev-parts.txt:

MMC Boot Partitions
===================

Read and write access is provided to the two MMC boot partitions. Due to
the sensitive nature of the boot partition contents, which often store
a bootloader or bootloader configuration tables crucial to booting the
platform, write access is disabled by default to reduce the chance of
accidental bricking.

To enable write access to /dev/mmcblkXbootY, disable the forced read-only
access with:

echo 0 > /sys/block/mmcblkXbootY/force_ro

==
- Chris.
--
Chris Ball <cjb@laptop.org> <http://printf.net/>
One Laptop Per Child