GUID-Disk: Default-Start-Partition

[kimi123]

Is there a way to change the default disk PC_EFI uses to boot on a GUID-Disk?

I have three OS-Installs and a partition for the Install-DVD on a single GUID-Disk.
 bash-3.2# diskutil list
/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *372.6 Gi   disk0
   1:                        EFI                         200.0 Mi   disk0s1
   2:                  Apple_HFS GPT1                    168.5 Gi   disk0s2
   3:                  Apple_HFS KALY1                   162.7 Gi   disk0s3
   4:                  Apple_HFS IATKOS                  35.9 Gi    disk0s4
   5:                  Apple_HFS Leopard_Install_Osx86   4.7 Gi     disk0s5


Right now the default start partition is 2 (GPT1). Is it possible to change that to partition 3 (KALY1)? Do I have to use GRUB?

Regards, Kimi

[kimi123]

I have found a solution to the problem.

If you have a GUID-disk (in my case disk1) with more than one partitions you need to have one of them be formatted as FAT32. Otherwise fdisk is not able to mark any partition as active. Sounds strange but its true for my board and sata-drives. Another guy has the same problems. Look at the Post of The Baron at Insanely.

GUID-Disk with EFI8: All partitions with hfs+: No Activation possible

Code:

/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *153.4 Gi   disk1
   1:                        EFI                         200.0 Mi   disk1s1
   2:                  Apple_HFS TOH                     145.9 Gi   disk1s2
   3:                  Apple_HFS INSTALL-DVD             7.0 Gi     disk1s3
bash-3.2# fdisk /dev/rdisk1
Disk: /dev/rdisk1 geometry: 20023/255/63 [321672960 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -  321672959] <Unknown ID>
 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     
bash-3.2# fdisk -e /dev/rdisk1
fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
Enter 'help' for information
fdisk: 1> update
Machine code updated.
fdisk:*1> f 2
Partition 2 marked active.
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
bash-3.2# fdisk /dev/rdisk1
Disk: /dev/rdisk1 geometry: 20023/255/63 [321672960 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -  321672959] <Unknown ID>
 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     

As you can see, after activation the partition is not activated: results in a boot 0 error


No lets do the the format of one partition with FAT.

Code:

/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *153.4 Gi   disk1
   1:                        EFI                         200.0 Mi   disk1s1
   2:                  Apple_HFS TOH                     145.9 Gi   disk1s2
   3:       Microsoft Basic Data INSTALL-DVD             7.0 Gi     disk1s3
bash-3.2# fdisk -e /dev/rdisk1
fdisk: could not open MBR file /usr/standalone/i386/boot0: No such file or directory
Enter 'help' for information
fdisk: 1> update
Machine code updated.
fdisk:*1> f 2
Partition 2 marked active.
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> quit
bash-3.2# fdisk /dev/rdisk1
Disk: /dev/rdisk1 geometry: 20023/255/63 [321672960 sectors]
Signature: 0xAA55
         Starting       Ending
 #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
------------------------------------------------------------------------
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>
*2: AF 1023 254  63 - 1023 254  63 [    409640 -  305957808] HFS+       
 3: 0B 1023 254  63 - 1023 254  63 [ 306629592 -   14781184] Win95 FAT-32
 4: 00    0   0   0 -    0   0   0 [         0 -          0] unused     
bash-3.2#

And with one FAT-Partition the activation was successful.

Greetings, Kimi