I had a perfectly booting system. When trying to resolve some problem getting another disk to boot, by doing "boot0cfg ada0", my system did no longer boot. I tried to fix this by doing: gpart bootcode -b /boot/pmbr ada0 but that did not work. I finally installed the pmbr from FreeBSD 9.1 and that gave me a booting system again. More people have reported problems booting with FreeBSD 10, and they seem very similar to what I have here: https://forums.freebsd.org/viewtopic.php?t=46014 Environment: System: FreeBSD bmach.nederware.nl 10.0-STABLE FreeBSD 10.0-STABLE #29 r268266: Sat Jul 5 10:51:50 NZST 2014 root@bmach.nederware.nl:/usr/obj/usr/src/10-STABLE/sys/BMACH amd64 How-To-Repeat: See description. Fix: Install FreeBSD 9.1. pmbr.
Disk partition: # gpart show ada0 => 34 312581741 ada0 GPT (149G) 34 128 1 freebsd-boot (64K) 162 33554432 2 freebsd-swap (16G) 33554594 279027181 3 freebsd-zfs (133G) Disk info: ada0 at ata2 bus 0 scbus0 target 0 lun 0 ada0: <ST3160815A 3.AAD> ATA-7 device ada0: Serial Number 9RA87APK ada0: 100.000MB/s transfers (UDMA5, PIO 8192bytes) ada0: 152627MB (312581808 512 byte sectors: 16H 63S/T 16383C) ada0: Previously was known as ad4 ada0 at ata2 bus 0 scbus0 target 0 lun 0 ada0: <ST3160815A 3.AAD> ATA-7 device ada0: Serial Number 9RA87APK ada0: 100.000MB/s transfers (UDMA5, PIO 8192bytes) ada0: 152627MB (312581808 512 byte sectors: 16H 63S/T 16383C) ada0: Previously was known as ad4 Hardware is from 2004 or earlier: Motherboard: INTEL DP965LT CPU: Intel(R) Core(TM)2 CPU 4400 @ 2.00GHz (1998.04-MHz K8-class CPU) PS: had the same problem with another disk, (the one I tried to fix), so it's not the disk.
Can you try reinstalling the 10.0 boot code and then running 'gpart set -a active ada0'? I'm wondering if this is the same the same issue as bug #194359 which I just reported...
Is this PR still relevant?