Problems with SD boot of FSO, OM 2008.8, add /dev/mmcblk0... to distros?

Alex Oberhauser oberhauseralex at networld.to
Sat Sep 20 18:25:17 CEST 2008


On Fri, Sep 19, 2008 at 09:58:21AM -0500, Dennis Ferron wrote:
> I think a number of people are having the same problem stemming from the sd
> card driver not reading some cards.  The mmcblk0p1, p2, etc. device files
> actually will be autocreated whenever Linux thinks there are partitions
> there, but the problem is that sometimes when it tries to read the partition
> table of the card it fails to get any data, so it doesn't think any
> partitions exist.  Thanks for posting the mknod syntax because I was
> wondering how you do that manually, but you can also do this to make the p1,
> p2, p3 device files show up automatically:
> fdisk /dev/mmcblk0
> visually verify that partition table exists
> use w to make fdisk write the (unchanged) partition table back out

Same problem here and the recovery of the partition table with fdisk works
for me.

> What happens is after the w command, fdisk calls ioctl to resync the
> partition table, and you magically get the dev files back.  (Don't save with
> w if fdisk thinks the partition table is empty though!)
> 
> In fact, would you try this and tell us if it works?  I'd like to verify
> we're all having the same problem and not different problems.

Seams to be the same problem.

> If the first time you call fdisk you get no table, try calling fdisk
> multiple times.  Here's an actual session capture.  fdisk is returning
> different results every time I call it:
> 
> root at om-gta02:~# fdisk -l /dev/mmcblk0
> root at om-gta02:~# fdisk -l /dev/mmcblk0

Also this behavior I have seen. If fdisk shows no output it was also not
possible to override the stuff with dd.

By the way I have a Sandisk 8 GB.

Alex




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