Date: Sun, 1 Dec 2019 11:33:36 -0700 From: Warner Losh <imp@bsdimp.com> To: Tomasz CEDRO <tomek@cedro.info> Cc: freebsd-questions@freebsd.org, "freebsd-usb@FreeBSD.org" <freebsd-usb@freebsd.org> Subject: Re: pendrive clone impossible ? Message-ID: <CANCZdfpmdOav9SmLJAMTZ-7EAf2MN3Gp%2BLNF63N_hf25HJWyBA@mail.gmail.com> In-Reply-To: <CAFYkXjkKRa3Fz6xuiCw0yHKsL6icVnJVLhD=P%2BX0ZqawEJ2N%2Bw@mail.gmail.com> References: <CAFYkXjkHobPfNwCL3ssL98TgUjE=jvojXACH%2BiR0EV-tzK-pxA@mail.gmail.com> <CAFYkXjkKRa3Fz6xuiCw0yHKsL6icVnJVLhD=P%2BX0ZqawEJ2N%2Bw@mail.gmail.com>
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On Sun, Dec 1, 2019, 10:22 AM Tomasz CEDRO <tomek@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 > > -- > CeDeROM, SQ7MHZ, http://www.tomek.cedro.info > _______________________________________________ > freebsd-usb@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-usb > To unsubscribe, send any mail to "freebsd-usb-unsubscribe@freebsd.org" >
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