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Old 09-26-2013, 08:37 PM   #3
knc1
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Join Date: Feb 2012
Location: Central Texas
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Quote:
Originally Posted by zigg View Post
Answered my own question—sort of—with further reading.

It may or may not be safe to exit USB Drive Mode with the drive zeroed. But it is definitely OK to erase specifically the filesystem part (skipping the MBR and partition table) using an overwrite erase tool of some kind (dd, OS X Disk Utility) followed by a FAT format.
Except of course, this is an eMMC (flash based) device.
What you write to is **NOT** the same eraseblock that previously held the data.
Your information can still be recovered from the "idle pool" of erase blocks on the device.

Doing a truly secure erase of a flash device takes more than user-land tools.
The diags "erase all" menu entry will do it.
But it will also do just what it says - blank the entire device.
Which can be a PITA to recover from.
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