USB Drive not showing up correctly in 8.1 (works in 7.3)
srandall52 at gmail.com
Sun Jan 16 19:31:10 UTC 2011
On Sun, 16 Jan 2011 11:00:01 -0700 (MST)
Warren Block <wblock at wonkity.com> wrote:
> On Sat, 15 Jan 2011, perryh at pluto.rain.com wrote:
> > Jerahmy Pocott <quakenet1 at optusnet.com.au> wrote:
> >> I have a USB Drive that was working fine under 7.3, but since
> >> updating to 8.1 no longer has the correct /dev entries. Under
> >> 7.3 it was da0s1, in 8.1 there is now only da0 and da0a, which
> >> shouldn't exist...
> da0s1 is MBR, da0a is "dangerously dedicated". I would not expect
> differences between 7 and 8 USB to show that on an existing drive. If
> the drive was reworked during the 7-to-8 upgrade--maybe with "bsdlabel
> auto"--that would be a more likely explanation.
The actual explanation is the new geom partitioners introduced in 8.0.
The disk has an MBR in block 0 and a forgotten BSD label (dangerously
dedicated) in block 1. 8.x sensibly ignores one of them; unfortunately
it ignores the MBR, not the unwanted BSD label.
The solution is:
# dd if=/dev/zero of=/dev/da0 seek=1 count=1
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