Bug 172653

After a fresh install from 9.0-RELEASE, using GPT, I get the following message:

gptboot: Invalid GPT backup header

The BTX loader starts successfully, the system boots properly, and I am able to use the system without issues.  'gpart recover ada0' gives a message 'ada0 recovering is not needed.'  I have not used gmirror or glabel; however, while using bsdinstall I did give each partition its own label when using Manual partition setup as per 3.7.2 in the FreeBSD handbook.

I checked this against 9.1-PRERELEASE using the 20121006 snapshot as well, with the same steps, and the issue still occurs.  I also tried using 9.1-PRERELEASE and automatic partitioning with GPT, and the issue occurs there too.

uname -a for that install:
FreeBSD babylon 9.1-PRERELEASE FreeBSD 9.1-PRERELEASE #0: Sat Oct  6 04:02:11 UTC 2012
root@build-i386-fbsd-2.albsd.org:/usr/oj/i386.i386/usr/src/sys/GENERIC  i386

I asked this question on the forums and it was suggested to submit a PR.  See http://forums.freebsd.org/showthread.php?p=193400

System:
Dell Latitude c840
A13 BIOS (latest)

gpart show ada0:
=>       34  312581741  ada0  GPT  (149G)
         34       1024     1  freebsd-boot  (512k)
       1058    4194304     2  freebsd-ufs  (2.0G)
    4195362    8388608     3  freebsd-swap  (4.0G)
   12583970    8388608     4  freebsd-ufs  (4.0G)
   20972578    8388608     5  freebsd-ufs  (4.0G)
   29361186  283115520     6  freebsd-ufs  (135G)
  312476706     105069        - free -  (51M)

Full dmesg:
Copyright (c) 1992-2012 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
	The Regents of the University of California. All rights reserved.
FreeBSD is a registered trademark of The FreeBSD Foundation.
FreeBSD 9.0-RELEASE #0: Tue Jan  3 07:15:25 UTC 2012
    root@obrian.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC i386
CPU: Intel(R) Pentium(R) 4 Mobile CPU 1.60GHz (1595.33-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0xf24  Family = f  Model = 2  Stepping = 4
  Features=0x3febf9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM>
real memory  = 1342177280 (1280 MB)
avail memory = 1295364096 (1235 MB)
kbd1 at kbdmux0
acpi0: <DELL CPi R  > on motherboard
acpi0: reservation of 0, 9fc00 (3) failed
acpi0: reservation of 100000, 4fef0000 (3) failed
Timecounter "ACPI-fast" frequency 3579545 Hz quality 900
acpi_timer0: <24-bit timer at 3.579545MHz> port 0x808-0x80b on acpi0
cpu0: <ACPI CPU> on acpi0
acpi_acad0: <AC Adapter> on acpi0
battery0: <ACPI Control Method Battery> on acpi0
battery1: <ACPI Control Method Battery> on acpi0
acpi_lid0: <Control Method Lid Switch> on acpi0
acpi_button0: <Power Button> on acpi0
acpi_button1: <Sleep Button> on acpi0
pcib0: <ACPI Host-PCI bridge> port 0xcf8-0xcff on acpi0
pci_link1: BIOS IRQ 11 for 0.31.INTB is invalid
pci0: <ACPI PCI bus> on pcib0
agp0: <Intel 82845 host to AGP bridge> on hostb0
pcib1: <ACPI PCI-PCI bridge> at device 1.0 on pci0
pci1: <ACPI PCI bus> on pcib1
vgapci0: <VGA-compatible display> mem 0xfc000000-0xfcffffff,0xe0000000-0xe7ffffff,0xdff80000-0xdfffffff irq 11 at device 0.0 on pci1
uhci0: <Intel 82801CA/CAM (ICH3) USB controller USB-A> port 0xbf80-0xbf9f irq 11 at device 29.0 on pci0
uhci0: LegSup = 0x2f00
usbus0: <Intel 82801CA/CAM (ICH3) USB controller USB-A> on uhci0
uhci1: <Intel 82801CA/CAM (ICH3) USB controller USB-C> port 0xbf20-0xbf3f irq 11 at device 29.2 on pci0
uhci1: LegSup = 0x2f00
usbus1: <Intel 82801CA/CAM (ICH3) USB controller USB-C> on uhci1
pcib2: <ACPI PCI-PCI bridge> at device 30.0 on pci0
pcib2: failed to allocate initial I/O port window: 0xe000-0xffff
pcib2: failed to allocate initial memory window: 0xf4000000-0xfbffffff
pci2: <ACPI PCI bus> on pcib2
xl0: <3Com 3c905C-TX Fast Etherlink XL> port 0xec80-0xecff mem 0xf8fffc00-0xf8fffc7f irq 11 at device 0.0 on pci2
miibus0: <MII bus> on xl0
ukphy0: <Generic IEEE 802.3u media interface> PHY 24 on miibus0
ukphy0:  none, 10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto, auto-flow
xl0: Ethernet address: 00:08:74:05:76:d8
cbb0: <TI4451 PCI-CardBus Bridge> at device 1.0 on pci2
cardbus0: <CardBus bus> on cbb0
pccard0: <16-bit PCCard bus> on cbb0
cbb1: <TI4451 PCI-CardBus Bridge> at device 1.1 on pci2
cardbus1: <CardBus bus> on cbb1
pccard1: <16-bit PCCard bus> on cbb1
fwohci0: <Texas Instruments PCI4451> mem 0xf8fff000-0xf8fff7ff,0xf8ff8000-0xf8ffbfff irq 11 at device 1.2 on pci2
fwohci0: OHCI version 1.0 (ROM=1)
fwohci0: No. of Isochronous channels is 4.
fwohci0: EUI64 42:4f:c0:00:0f:d6:54:21
fwohci0: Phy 1394a available S400, 1 ports.
fwohci0: Link S400, max_rec 2048 bytes.
firewire0: <IEEE1394(FireWire) bus> on fwohci0
dcons_crom0: <dcons configuration ROM> on firewire0
dcons_crom0: bus_addr 0x1704000
fwe0: <Ethernet over FireWire> on firewire0
if_fwe0: Fake Ethernet address: 42:4f:c0:d6:54:21
fwe0: Ethernet address: 42:4f:c0:d6:54:21
fwip0: <IP over FireWire> on firewire0
fwip0: Firewire address: 42:4f:c0:00:0f:d6:54:21 @ 0xfffe00000000, S400, maxrec 2048
fwohci0: Initiate bus reset
fwohci0: fwohci_intr_core: BUS reset
fwohci0: fwohci_intr_core: node_id=0x00000000, SelfID Count=1, CYCLEMASTER mode
iwi0: <Intel(R) PRO/Wireless 2200BG> mem 0xf8ffe000-0xf8ffefff irq 11 at device 3.0 on pci2
isab0: <PCI-ISA bridge> at device 31.0 on pci0
isa0: <ISA bus> on isab0
atapci0: <Intel ICH3 UDMA100 controller> port 0x1f0-0x1f7,0x3f6,0x170-0x177,0x376,0xbfa0-0xbfaf at device 31.1 on pci0
ata0: <ATA channel 0> on atapci0
ata1: <ATA channel 1> on atapci0
pcm0: <Intel ICH3 (82801CA)> port 0xd800-0xd8ff,0xdc80-0xdcbf irq 9 at device 31.5 on pci0
pcm0: <Cirrus Logic CS4205 AC97 Codec>
pci0: <simple comms, generic modem> at device 31.6 (no driver attached)
acpi_tz0: <Thermal Zone> on acpi0
atkbdc0: <Keyboard controller (i8042)> port 0x60,0x64 irq 1 on acpi0
atkbd0: <AT Keyboard> irq 1 on atkbdc0
kbd0 at atkbd0
atkbd0: [GIANT-LOCKED]
psm0: <PS/2 Mouse> irq 12 on atkbdc0
psm0: [GIANT-LOCKED]
psm0: model GlidePoint, device ID 0
atrtc0: <AT realtime clock> port 0x70-0x71,0x72-0x77 irq 8 on acpi0
Event timer "RTC" frequency 32768 Hz quality 0
attimer0: <AT timer> port 0x40-0x43,0x50-0x53 irq 0 on acpi0
Timecounter "i8254" frequency 1193182 Hz quality 0
Event timer "i8254" frequency 1193182 Hz quality 100
fdc0: <floppy drive controller (FDE)> port 0x3f2-0x3f5,0x3f7 irq 6 drq 2 on acpi0
fd0: <1440-KB 3.5" drive> on fdc0 drive 0
uart0: <Non-standard ns8250 class UART with FIFOs> port 0x3f8-0x3ff irq 4 flags 0x10 on acpi0
ppc0: <Parallel port> port 0x378-0x37f,0x778-0x77b irq 7 drq 3 on acpi0
ppc0: SMC-like chipset (ECP/EPP/PS2/NIBBLE) in COMPATIBLE mode
ppc0: FIFO with 16/16/8 bytes threshold
ppbus0: <Parallel port bus> on ppc0
plip0: <PLIP network interface> on ppbus0
lpt0: <Printer> on ppbus0
lpt0: Interrupt-driven port
ppi0: <Parallel I/O> on ppbus0
pmtimer0 on isa0
orm0: <ISA Option ROMs> at iomem 0xc0000-0xcf7ff,0xcf800-0xcffff pnpid ORM0000 on isa0
sc0: <System console> at flags 0x100 on isa0
sc0: VGA <16 virtual consoles, flags=0x300>
vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
acpi_perf0: <ACPI CPU Frequency Control> on cpu0
acpi_perf0: failed in PERF_STATUS attach
device_attach: acpi_perf0 attach returned 6
acpi_perf0: <ACPI CPU Frequency Control> on cpu0
acpi_perf0: failed in PERF_STATUS attach
device_attach: acpi_perf0 attach returned 6
p4tcc0: <CPU Frequency Thermal Control> on cpu0
ichss0: <SpeedStep ICH> on cpu0
Timecounters tick every 1.000 msec
firewire0: 1 nodes, maxhop <= 0 cable IRM irm(0)  (me) 
firewire0: bus manager 0 
usbus0: 12Mbps Full Speed USB v1.0
usbus1: 12Mbps Full Speed USB v1.0
ugen0.1: <Intel> at usbus0
uhub0: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus0
ugen1.1: <Intel> at usbus1
uhub1: <Intel UHCI root HUB, class 9/0, rev 1.00/1.00, addr 1> on usbus1
ada0 at ata0 bus 0 scbus0 target 0 lun 0
ada0: <SAMSUNG HM160HC LQ100-10> ATA-8 device
ada0: 100.000MB/s transfers (UDMA5, PIO 8192bytes)
ada0: 152627MB (312581808 512 byte sectors: 16H 63S/T 16383C)
ada0: Previously was known as ad0
Timecounter "TSC" frequency 1595325936 Hz quality 800
cd0 at ata0 bus 0 scbus0 target 1 lun 0
cd0: <HL-DT-ST RW/DVD GCC-4241N A100> Removable CD-ROM SCSI-0 device 
cd0: 33.300MB/s transfers (UDMA2, ATAPI 12bytes, PIO 65534bytes)
cd0: Attempt to query device size failed: NOT READY, Medium not present
uhub0: 2 ports with 2 removable, self powered
uhub1: 2 ports with 2 removable, self powered
ugen0.2: <vendor 0x15d9> at usbus0
ums0: <vendor 0x15d9 USB Mouse, class 0/0, rev 1.10/1.00, addr 2> on usbus0
ums0: 3 buttons and [XYZ] coordinates ID=0
Trying to mount root from ufs:/dev/ada0p2 [rw]...
wlan0: Ethernet address: 00:16:6f:b5:eb:8a
iwi0: need multicast update callback
iwi0: need multicast update callback
iwi0: need multicast update callback

How-To-Repeat: Steps to Reproduce:
1. Launch from boot media based on the 9.0-RELEASE i386 ISO or RELENG_9 Snapshot 20121006.
2. Boot into bsdinstall.
3. Select to NOT use a custom keyboard layout.
4. Set a hostname ('babylon' was used here).
5. Select all available components and continue.
6. When prompted for the install type, select either Guided or Manual.
 - If selecting Guided, use the whole disk, and select Finish to accept defaults.
 - If selecting Manual, use GPT, and set up the system as listed in the 'gpart show ada0' output as listed in the 'Full Description' above.
7. Commit all changes to the filesystem.
8. Allow the installation to proceed.
9. Perform normal post-install tasks - root password, adding one new user, setting EDT as the time zone, etc.
10. When prompted, restart the system.

Observed:
Prior to the BTX loader being executed, the following error is seen:

gptboot: Invalid backup GPT header

The BTX loader does load, the system will boot, and there appears to be no affect to stability, although extensive benchmarking or testing has NOT been performed.

Expected:
No messages should appear prior to BTX loader executing.