pendrive clone impossible ?

[Warner Losh]

On Sun, Dec 1, 2019, 10:22 AM Tomasz CEDRO <tomek at cedro.info> wrote:

> As my previous message got moderated, just a quick summary - looks
> like a GEOM_PART silently discards writes to MBR with a DD when it
> considers MBR broken (writing to the rest of the disk is possible). I
> have reported this as error:
>

I'm sorry, but you are wrong. It does no such thing. The error posted is on
close when geom retastes the drive and finds bogus data. Geom *never*
changes a write, ever, nor does it filter them. Gpart is not even looped in
when writing to the raw disk with dd, though it may indirectly deny the
open of the device. Debug flags 16 permits the open, but has no other
effect.

Some thumb drive have antivirus protection that will reject a write that is
bogus.

Warner


https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=242341
>
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> CeDeROM, SQ7MHZ, http://www.tomek.cedro.info
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