Date: Tue, 13 Jan 2009 21:55:39 +0000 (UTC) From: Luigi Rizzo <luigi@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r187195 - head/usr.sbin/boot0cfg Message-ID: <200901132155.n0DLtdIe017395@svn.freebsd.org>
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Author: luigi Date: Tue Jan 13 21:55:39 2009 New Revision: 187195 URL: http://svn.freebsd.org/changeset/base/187195 Log: Extend the geom-related info and put in the NOTE section, not in BUGS, as this is a feature. Bump the date, as it was forgotten in previous commits and the page has had significant changes recently Modified: head/usr.sbin/boot0cfg/boot0cfg.8 Modified: head/usr.sbin/boot0cfg/boot0cfg.8 ============================================================================== --- head/usr.sbin/boot0cfg/boot0cfg.8 Tue Jan 13 21:19:27 2009 (r187194) +++ head/usr.sbin/boot0cfg/boot0cfg.8 Tue Jan 13 21:55:39 2009 (r187195) @@ -24,7 +24,7 @@ .\" .\" $FreeBSD$ .\" -.Dd June 7, 2007 +.Dd January 13, 2009 .Dt BOOT0CFG 8 .Os .Sh NAME @@ -153,6 +153,21 @@ Set the timeout value to .It Fl v Verbose: display information about the slices defined, etc. .El +.Sh NOTE +Protection mechanisms in the +.Xr geom 4 +subsystem might prevent +.Nm +from being able to update the MBR on a mounted disk. +Instructions for temporarily disabling these protection mechanisms +can be found in the +.Xr geom 4 +manpage. Specifically, do a +.Pp +.Dl sysctl kern.geom.debugflags=0x10 +.Pp +to allow writing to the MBR, and restore it to 0 afterwards. +.Pp .Sh FILES .Bl -tag -width /boot/boot0sio -compact .It Pa /boot/boot0 @@ -186,16 +201,6 @@ to install the default MBR: .Sh AUTHORS .An Robert Nordier Aq rnordier@FreeBSD.org . .Sh BUGS -Protection mechanisms in the -.Xr geom 4 -subsystem might prevent -.Nm -from being able to update the MBR on a mounted disk. -Instructions for temporarily disabling these protection mechanisms -can be found in the -.Xr geom 4 -manpage. -.Pp Use of the .Sq packet option may cause @@ -204,6 +209,6 @@ to fail, depending on the nature of BIOS .Pp Use of the .Sq setdrv -option with an incorrect -d operand may cause the MBR to be written -to the wrong disk. -Be careful! +option with an incorrect -d operand may cause the boot0 code +to write the MBR to the wrong disk, thus trashing its previous +content. Be careful.
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