Date: Sun, 29 Apr 2018 23:05:40 +0200 From: Polytropon <freebsd@edvax.de> To: Manish Jain <jude.obscure@yandex.com> Cc: Robert Fitzpatrick <robert@webtent.org>, FreeBSD <freebsd-questions@freebsd.org> Subject: Re: Restoring bootcode Message-ID: <20180429230540.c93489c9.freebsd@edvax.de> In-Reply-To: <ac24f0a3-59d6-6b14-0342-e935c29bf5fe@yandex.com> References: <5AE5F327.3050702@webtent.org> <ac24f0a3-59d6-6b14-0342-e935c29bf5fe@yandex.com>
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On Sun, 29 Apr 2018 23:48:04 +0530, Manish Jain wrote: > On 04/29/18 22:00, Robert Fitzpatrick via freebsd-questions wrote: > > Something happens to the bootcode since an upgrade a while back and I've > > been starting this 10.4-RELEASE server at the loader OK prompt using > > 'set currdev=disk0s1a' and then boot. Here is the server system... > > > > root@dev:~ # gpart show > > => 63 41942977 ada0 MBR (20G) > > 63 41929587 1 freebsd [active] (20G) > > 41929650 13390 - free - (6.5M) > > > > => 0 41929587 ada0s1 BSD (20G) > > 0 1024000 1 freebsd-ufs (500M) > > 1024000 524288 2 freebsd-swap (256M) > > 1548288 20480000 4 freebsd-ufs (9.8G) > > 22028288 19901299 5 freebsd-ufs (9.5G) > > > > I've tried the following to install the boot code, but still ending up > > at the loader prompt... > > > > root@dev:~ # gpart bootcode -b /boot/mbr ada0 > > bootcode written to ada0 > > > > I also tried with ada0s1 with same result. Clearly I don't understand > > how to get this done, can someone help? > > > > Hi Robert, > > /boot/mbr needs you to set ada0s1 as the active partition. The easier > solution in your case perhaps is: > > gpart bootcode -b /boot/boot0 ada0 > gpart bootcode -b /boot/boot ada0s1 As this seems to be a MBR setup, the commands should probably be: # gpart bootcode -b /boot/mbr ada0 # gpart set -a active -i 1 ada0 # gpart bootcode -b /boot/boot ada0s1 Step 1 will add the regular MBR boot code, assuming this is a FreeBSD-only system (no boot manager required). Step 2 covers the case where the "active" flag has accidentally been cleared; make sure it is set again (so the system will recognize the partition s1 as being active, and attempt booting by transfering control to it). Step 3 will install the kernel loading mechanism for the slice that hosts the FreeBSD partitions (and therefore continue booting the kernel from /boot/kernel/kernel on /dev/ada0s1a, its default location). See "man 8 boot" and "man gpart" (sec. EXAMPLES). Further reading: http://www.wonkity.com/~wblock/docs/html/disksetup.html#_the_old_standard_mbr :-) -- Polytropon Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ...home | help
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