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Date:      Sun, 03 May 2015 10:22:29 -0453
From:      "William A. Mahaffey III" <>
Subject:   Re: How to restore a USB drive converted to bootable
Message-ID:  <>
In-Reply-To: <>
References:  <> <> <> <>

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On 05/03/15 05:36, Dave wrote:
> On Saturday 02 May 2015 17:59:02 William A. Mahaffey III wrote:
>> On 05/02/15 17:30, Polytropon wrote:
>>> On Sat, 02 May 2015 17:23:13 -0453, William A. Mahaffey III wrote:
>>>> On 05/02/15 16:45, Polytropon wrote:
>>>>> On Sat, 02 May 2015 09:20:09 -0453, William A. Mahaffey III wrote:
>>>>>> On 05/02/15 09:06, Lowell Gilbert wrote:
>>>>>>> "William A. Mahaffey III" <> writes:
>>>>>>>> I am about to do some OS installs (NetBSD & OpenBSD, as it happens) on
>>>>>>>> boxen under construction. I would also like to use UBCD on a flash
>>>>>>>> drive to memcheck those boxen prior to installation. If I prep a USB
>>>>>>>> thumb drive as either a bootable UBCD drive or an over-the-WWW
>>>>>>>> installer, I wipe out the drive for its original use. Is there a way
>>>>>>>> to restore the drive back to its original functionality if I wanted to
>>>>>>> Is "wipe the drive and reformat" what you need to hear, or do you have
>>>>>>> more requirements that you haven't made clear?
>>>>>> Wipe & reformat, preferably from CLI under FBSD 9.3R-p13 for
>>>>>> convenience, is what I'm after. Clearly creating a bootable UBCD or
>>>>>> installer will wipe out whatever was
>>>>>> there before, so I just want to get back to 'virgin' USB drive.
>>>>> In that case, the command
>>>>> 	# dd if=/dev/zero of=/dev/da0 bs=1m count=1
>>>>> should be fine. If there is any offending GPT metadata located
>>>>> at the end of the USB drive, estimate the size and also erase
>>>>> the last few MBs (use skip= to do so). There is no need to
>>>>> actually zero out the _whole_ drive.
>>>> *Aaaaaaaaaaaaaaahhhhh*, I wasn't sure about that (zero the whole drive),
>>>> thanks :-) ....
>>> There are only few significant "data zones" on the USB drive.
>>> The boot sector and partition table are located at the beginning,
>>> and _maybe_ GPT metadata at the end. Removing both makes the
>>> remaining bits and bytes practically useless (except when you
>>> take it to forensics, but you don't want to recover things
>>> anyway, so the result should work for you).
>>> However, if you want a USB drive "new" (as in "I just bought it
>>> from the shop, it's fresh out of the package!"), then you have
>>> to write a MSDOS (FAT) file system, install some crapware, some
>>> ridiculous "drivers", and "value added" software, maybe with
>>> some spying tools, malware, nagware, and non-working "encryption"
>>> tools. Add several partitions and make them smaller than the
>>> real size of the drive. And add a "Facebook" link. :-)
>> I was thinking of dd-ing the 1st MB or 2 off into a file, then restoring
>> from that file when done, that would skip all the extra features you
>> mention ;-). Would 1 or 2 MB be enough to get all of the FS info ? I
>> wasn't aware you didn't have to zero everything out, that simplifies
>> things a fair bit ....
> That might be enough if you are then going to put it in a drawer, not use
> it all, then restore those same few MB later.
> If you are planning on installing UBCD onto it in a some form of bootable
> filesystem them I'd suggest you need to DD *at least* the size of UBCD so
> you can restore any/all existing data.
> You could just DD the entire pendrive and pipe it through tar/gzip if you
> really want to be able to put back exactly as you found it since you don't
> really know exactly where on the drive the data is.
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I'm not sweating the data, just the functionality .... If I overwrite it 
w/ UBCD or something similar, I know I lose all data there, so that's no 
problem, I just want to (possibly) be able to revert to previous 
functionality ....


	William A. Mahaffey III


	"The M1 Garand is without doubt the finest implement of war
	 ever devised by man."
                            -- Gen. George S. Patton Jr.

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