[wplug] Strange fdisk/parted behavior with 4G SD card

[Tim Lesher]

I'm seeing a consistent behavior I can't explain when trying to partition a
4GB SD card using either fdisk (version 2.13.1) or parted (1.7.1) (using
Ubuntu 8.04 amd64).

What I want is three (primary) partitions of ~725MB each; the remainder is
an extended partition with a single 1GB logical partition. fdisk and parted
each appear to do the right thing, but when I later try to make filesystems
on the partitions, the partition table is trash--fdisk and parted each says
the disklabel is corrupt.

===== Paraphrased transcript =====
So, fdisk on a clean msdos-style disklabel:

Disk /dev/sdd: 4241 MB, 4241489920 bytes
131 heads, 62 sectors/track, 1019 cylinders
Units = cylinders of 8122 * 512 = 4158464 bytes
Disk identifier: 0xbe7cee25

[n]ew, [p]rimary, number [1], first cylinder=[1], size=[+725M].
[n]ew, [p]rimary, number [2], first cylinder=[176], size=[+725M].
[n]ew, [p]rimary, number [3], first cylinder=[351], size=[+725M].
[n]ew, [e]xtended, first cylinder=[526], last cylinder=[1019]
[n]ew, first cylinder=[526], size=[+1024M]

All done. [p] shows a happy partition table:

Disk /dev/sdd: 4241 MB, 4241489920 bytes
131 heads, 62 sectors/track, 1019 cylinders
Units = cylinders of 8122 * 512 = 4158464 bytes
Disk identifier: 0xbe7cee25

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1         175      710644   83  Linux
/dev/sdd2             176         350      710675   83  Linux
/dev/sdd3             351         525      710675   83  Linux
/dev/sdd4             526        1019     2006134    5  Extended
/dev/sdd5             526         772     1003036   83  Linux

[w]rite, then run fdisk again:

Warning: ignoring extra data in partition table 5
Warning: ignoring extra data in partition table 5
Warning: ignoring extra data in partition table 5
Warning: invalid flag 0xffff of partition table 5 will be corrected by
w(rite)

Command (m for help): p

Disk /dev/sdd: 4241 MB, 4241489920 bytes
131 heads, 62 sectors/track, 1019 cylinders
Units = cylinders of 8122 * 512 = 4158464 bytes
Disk identifier: 0xbe7cee25

   Device Boot      Start         End      Blocks   Id  System
/dev/sdd1               1         175      710644   83  Linux
/dev/sdd2             176         350      710675   83  Linux
/dev/sdd3             351         525      710675   83  Linux
/dev/sdd4             526        1019     2006134    5  Extended
/dev/sdd5   ?      529332     1058139  2147483647+  ff  BBT

=== End paraphrased transcript ===

Any ideas what could be happening to the partition table?
-- 
Tim Lesher <tlesher at gmail.com>
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