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How to change default boot system in Darwin


ricren
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Hi,

The internal hard drive of my Hackintosh notebook is partitioned in 3. Two of them have Mac OS systems installed.

I can choose which system to boot from the Darwin boot page and as usual, there's one of them that is the default system.

 

Could anybody tell me how can I change the default system? In my real Mac I can do it from "startup system " panel, but in this case for same reason I can not see any system appearing in that panel. And Acronis OS director only see the default one.

 

Thanks

 

Ric

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If you have a Vista disk you can go into repair system and then cmd and list partition and choose the one you want to be active. Or you can probably fdisk it that way too, Im not sure though.

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if you want to change the default boot partition on drive 0 (the first disk) use these (case sensitive) commands in terminal.

 

'sudo FDISK -e /dev/rdisk0' (or /dev/rdisk1 etc.)

 

'h' will show the Command help list

'm' will show the manual ('q' to return to FDISK)

 

'p' will show the partitions where * marks the boot partition

'f 2' will flag partition 2 as boot partition.

 

'q' to quit and 'y' to save

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thanks a lot for your answer. However, following this procedure fails to make it active. This is a copy of the terminal log:

----------------------------------------------------------------------------------------------------

Last login: Thu Jun 21 21:08:10 on console

Welcome to Darwin!

Pipa:~ ricren$ sudo FDISK -e /dev/rdisk0

Password:

Enter 'help' for information

fdisk: 1> p

Disk: /dev/rdisk0 geometry: 12161/255/63 [195371568 sectors]

Offset: 0 Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: 0B 0 1 1 - 1023 32 57 [ 63 - 31457280] Win95 FAT-32

*2: AF 1023 32 58 - 1023 139 63 [ 31457343 - 20971572] HFS+

3: AF 1023 140 1 - 1023 171 57 [ 52428915 - 31457280] HFS+

4: 0B 1023 172 1 - 1023 254 63 [ 83886201 - 111480264] Win95 FAT-32

fdisk: 1> f 3

Partition 3 marked active.

fdisk:*1> q

Writing current MBR to disk.

Device could not be accessed exclusively.

A reboot will be needed for changes to take effect. OK? [n] y

Pipa:~ ricren$

-------------------------------------------------------------------------------------

 

When I reboot, the partition 2 keeps active. NO matter what.

I wonder: Is there any place inside the system where I could edit this entry manually?

 

thanks again

 

Ric

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Darwin essentially boots the first partition it finds, unless told otherwise at the f8 prompt.. the only method I have tried, which is both dubious & risky, but worked for me when I tested it, was to edit the partition table so the entries are in a different order to their order on-disk, making a different one "first".

 

 

I don't recommend this, unless you're experimenting on a fully backed up & semi-expendable system.

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I wonder, if Darwin essentially boots the first partition it finds, what happens if I erase the OS installation in partition 2, do you think it would go and automatically boot from partition 3 instead? Or it will just stay saying that it can not find a valid OS in partition 2?

 

Any commentaries appreciated. I'm feed up of having to choose partition 3 manually at boot time.

 

thanks

 

Ric

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  • 1 year later...
thanks a lot for your answer. However, following this procedure fails to make it active. This is a copy of the terminal log:

----------------------------------------------------------------------------------------------------

Last login: Thu Jun 21 21:08:10 on console

Welcome to Darwin!

Pipa:~ ricren$ sudo FDISK -e /dev/rdisk0

Password:

Enter 'help' for information

fdisk: 1> p

Disk: /dev/rdisk0 geometry: 12161/255/63 [195371568 sectors]

Offset: 0 Signature: 0xAA55

Starting Ending

#: id cyl hd sec - cyl hd sec [ start - size]

------------------------------------------------------------------------

1: 0B 0 1 1 - 1023 32 57 [ 63 - 31457280] Win95 FAT-32

*2: AF 1023 32 58 - 1023 139 63 [ 31457343 - 20971572] HFS+

3: AF 1023 140 1 - 1023 171 57 [ 52428915 - 31457280] HFS+

4: 0B 1023 172 1 - 1023 254 63 [ 83886201 - 111480264] Win95 FAT-32

fdisk: 1> f 3

Partition 3 marked active.

fdisk:*1> q

Writing current MBR to disk.

Device could not be accessed exclusively.

A reboot will be needed for changes to take effect. OK? [n] y

Pipa:~ ricren$

-------------------------------------------------------------------------------------

 

When I reboot, the partition 2 keeps active. NO matter what.

I wonder: Is there any place inside the system where I could edit this entry manually?

 

thanks again

 

Ric

 

It looks like you tried running FDISK from the same physical drive you booted from. note the line "Device could not be accessed exclusively." Try booting off of another physical drive and running FDISK.

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