Invalid fdisk partition table found

[Lowell Gilbert]

Robert <traveling08 at cox.net> writes:

> Greetings
>
> [robert at dell64] ~> uname -a
> FreeBSD dell64.shasta204.local 8.2-STABLE FreeBSD 8.2-STABLE #34: Fri
> Nov 18 06:43:01 PST 2011
> root at dell64.shasta204.local:/usr/obj/usr/src/sys/GENERIC  amd64 
>
> I have two Lexar Professional 600X 16GB compact flash cards that are
> unusable. fdisk shows:
>
> [robert at dell64] ~> fdisk /dev/da1
> ******* Working on device /dev/da1 *******
> parameters extracted from in-core disklabel are:
> cylinders=29 heads=64 sectors/track=32 (2048 blks/cyl)
>
> parameters to be used for BIOS calculations are:
> cylinders=29 heads=64 sectors/track=32 (2048 blks/cyl)
>
> fdisk: invalid fdisk partition table found
> Media sector size is 512
> Warning: BIOS sector numbering starts with sector 1
> Information from DOS bootblock is:
> The data for partition 1 is:
> sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
>     start 32, size 59360 (28 Meg), flag 80 (active)
> 	beg: cyl 0/ head 1/ sector 1;
> 	end: cyl 28/ head 63/ sector 32
> The data for partition 2 is:
> <UNUSED>
> The data for partition 3 is:
> <UNUSED>
> The data for partition 4 is:
> <UNUSED>
>
> It shows only 28 MB instead of 16GB. I have tried to change the type
> from 165 (FreeBSD) to msdosfs types 6 11 or 12 using fdisk -u and fdisk
> -i and also "sade". I do not get an error but when finished it still
> shows the same data. 
>
> I have tried to zero it out using " dd if=/dev/zero of=/dev/da1 bs=1m
> and nothing changes. I have tried different block sizes and counts to
> no avail.

If you zero it out and fdisk still sees a partition table, the write
probably didn't really happen. [Modulo some possible issues with the
kernel caching the disk parameters.] fdisk is sometimes a bit quiet
about its errors, but dd isn't...