HOWTO: Update firmware *without* reformat/reinstall

[shteve]

As has already been posted, the bootcamp-related firmware update fails to work if the mac has been XOM'd with blanka's patch. This is because the MBR partition type is being used and the firmware update expects GPT.

To go back to using the GPT I did these three things:

1. Changed the MBR partition records to point to EFI's GPT.

$ sudo fdisk -e /dev/rdisk0
fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
Enter 'help' for information
fdisk: 1> erase
fdisk:*1> edit 1
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
Partition id ('0' to disable)  [0 - FF]: [0] (? for help) EE
Do you wish to edit in CHS mode? [n] 
Partition offset [0 - 117210240]: [63] 1
Partition size [1 - 117210239]: [117210239] (press Enter here)
fdisk:*1> p
Disk: /dev/rdisk0       geometry: 7296/255/63 [117210240 sectors]
Offset: 0       Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE    0   0   2 - 1023 254  63 [         1 -  117210239] 
 2: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 3: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused      
fdisk:*1> w
Device could not be accessed exclusively.
A reboot will be needed for changes to take effect. OK? [n] y
Writing MBR at offset 0.
fdisk: 1> q
$

2. Removed nvram settings for booting, so it doesn't point to the now-defunct MBR partitions.

$ sudo nvram -d efi-boot-device
$ sudo nvram -d efi-boot-device-data
$ sudo nvram -d efi-apple-payload0
$ sudo nvram -d efi-apple-payload0-data

3. Reblessed the boot.efi in /System/Library/CoreServices.

$ bless --folder /System/Library/CoreServices --file /System/Library/CoreServices/boot.efi --setBoot

After that it booted up into Mac OS X and I was able to run the firmware update successfully.

[shteve]

Forgot to mention, this is on a Mac Mini Solo. Don't know how well this would work on other intel macs ..

Also before you do this make a (paper) note of your existing MBR partition table! When I reblessed xom.efi after the firmware update it wouldn't add XP's NTFS partition to the MBR and I had to do it manually from OSX for it to work.

[das]

Ok, so this is how to update the firmware, but how can you use Boot Camp? It only works if there is only one HFS+ partition on the drive to begin with...

[Capt. Kyle]

I am confirming that this method DOES work on a 20" iMac(Intel).

Thanks!

[shteve]

Originally Posted by das

Ok, so this is how to update the firmware, but how can you use Boot Camp? It only works if there is only one HFS+ partition on the drive to begin with...

When back in GPT mode with the new firmware and 10.4.6, it lets me burn the drivers CD successfully. I got it to boot the windows install CD too, but it showed the entire disk as being available for XP to install on and when I rebooted it showed "No bootable device -- insert boot disk and press any key" in textmode. I couldn't get that to go away until I cleared the efi-boot-device entries from the NVRAM (using the install disc), at which point it booted into OSX properly again.

[DonCalzone]

Worked on my MacBook Pro 2.0Ghz.

Not only that, but Bootcamp says my partitions are cool as well, and it sees windows is on the other partition

I can't boot up from it, and I will likely re-install Windows, but im glad i dont have to touch the OSX side.

[Alex Oughton]

Don't ask me why, but this resulted in the death of my partition.

Ah well, never mind. At least I have a backup!

Just a warning to anyone who doesn't...

[Birdy27]

Thank you so much for posting your solution.

I'm really glad I didn't have to format anything.

[antizeit]

Originally Posted by shteve

Forgot to mention, this is on a Mac Mini Solo. Don't know how well this would work on other intel macs ..

Also before you do this make a (paper) note of your existing MBR partition table! When I reblessed xom.efi after the firmware update it wouldn't add XP's NTFS partition to the MBR and I had to do it manually from OSX for it to work.

Great Work!

Unfortunatly - i didn´t read your second post in time - now i´m stuck with osx and disk-utility seeing my (old onmac-solution) xp partition and even listing it as a boot volume while in osx - but bootcamp doesn´t see it. When i tried to reinstall from the windows cd, it only showed the osx partition.

I guess my MBR-Partition table is broken and i would like to fix it "manually from OSX" like you stated, but since my unix-knowledge is close to zero and i don´t have the note with my old MBR Partition Table, i´m pretty much lost - can someone give me a hint on how to fix this?

thanks in advance & cheers
antizeit

[shteve]

Originally Posted by Alex Oughton

Don't ask me why, but this resulted in the death of my partition.

Ah well, never mind. At least I have a backup!

Just a warning to anyone who doesn't...

Sorry to hear that, I hope you get all your stuff back working fine!