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Fixing the b0 error


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#1
adlai

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I get a b0 error if I try to boot OS X without the install cd in the drive. With the install cd in the drive it boots and everything works fine.

How do I get rid of the b0 error? I do not want to wipe and reformat too

#2
Rammjet

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During setup of the partition, did you set the Mac partition "active"?

If not, find Fdisk and go here.

Be sure you select the correct disk if you have more than one.

#3
cardinal

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fdisk should be included on osx setup dvd. boot from dvd, hit f8 to get the prompt, and type -s to start in single mode with command line. i forget what exactly to type then, but it is something like fdisk <some param> /dev/rdisk0 assuming it is your first or only drive. the param you want is to drop into edit mode... just type fdisk by itself and it will give you a short summary of options. once you are in this mode, you will get fdisk> prompt. now type help to see available commands. i think it is show or print to view partitions on this drive. the partition with * before partition number is set to active. i assume none of yours will be. again, "help" will tell you how to set it active, so type <whatever command> <partition number> then do show/print again and it will have a star. then type quit or exit or whatever (see output of "help" command)and reboot. sorry about vague instructions, but i'm not at my hackintosh. it should be reasonably easy to figure it out. there is no need to bother downloading linux or msdos fdisk, you already have what you need.

#4
adlai

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it looks like I didn't. I have seen that in the forums, I did a throough search. I don't quite understand how to do it though, because when I try in terminal I get this "don't have permissions" message. Can someone give me a line-by-line walkthrough of what I have to do?

#5
-TiLT-

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Create a bootdisk that lets you load a dos-like command prompt. (E.g. Win95-98,WinME bootdisk) http://www.bootdisk.com/bootdisk.htm
download extended fdisk http://www.mecronome...sk/download.php
put it on your bootdisk
boot from it
run extended fdisk
choose the osx partition (the on that has an AF flag)
press enter, choose activate partition, press F3 answer yes to write the partition table
reboot

#6
Rammjet

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it looks like I didn't. I have seen that in the forums, I did a throough search. I don't quite understand how to do it though, because when I try in terminal I get this "don't have permissions" message. Can someone give me a line-by-line walkthrough of what I have to do?


I haven't tried this, but...to make your MacOSX partition active after a b0 error:

Boot into Windows.
  • click: Start -> Run
  • type: diskpart (enter)
  • type: list disk (enter) <--- to locate the number of the mac disk, probably 0
  • type: select disk 0 (enter) <--- use number from prev step
  • type: list partition (enter) <--- to locate the identifier for the partition for MacOSX
  • type: select partition x (enter) <--- where x is the MacOSX partition identifier from prev step
  • type: set active (enter) <--- bingo!
  • type: exit (enter)
reboot into MacOSX

#7
adlai

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dammit. So I decided to just do a wipe of the disk and start over. I mounted the drive on a usb connection, and used the winXp disk management utility to make a new partition, and mark it as active. Well, I did that, and then I reinstalled OS X. SAME PROBLEM. WTF.

#8
cardinal

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boot with install DVD, hit F8 to get the prompt, and type -s to start in single mode.

when it boots to command prompt, type fdisk -e /dev/rdisk0

I am assuming you only have 1 hard drive. If you have more then one, then it could be /dev/rdisk1 and so on. You will get fdisk prompt. then type "show". Output will look like:

fdisk: 1> print
Disk: /dev/rdisk0 geometry: 24321/255/63 [390721968 sectors]
Offset: 0 Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
*1: AF 0 1 1 - 1023 254 63 [ 63 - 390721905] HFS+
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

See the * before partition 1? That means it is active, ie, bios will try to boot from it. If you don't see a *, there is no partition set to active, and you won't boot. To set a partition to active, type:

flag 1 (or whatever partition number it is, likely 1)

Then type quit to save changes and exit. type reboot to reboot, remove the DVD and you should be booting into OSX.

Maybe what you will see instead will look scrambled and it won't see an HFS+ partition. I think this happened to me at one point while I was trying to install. Then try this (but you will have to reinstall OSX after that):

fdisk -i /dev/rdisk0 (this will reinitialize MBR, just in case)
fdisk -a hfs /dev/rdisk0 (this will make one HFS+ partition that takes the whole disk)

then make this partition active, as described at start of this post.

Reboot from DVD, install OSX into the partition you see (don't erase it, just install into it), and you should be able to boot from hard drive. If you can't, do step 1 again to make sure install program didn't make it inactive again.

I'm sure there are many far more user friendly ways to do this, but I found it easier to just use what was provided already on install DVD.

#9
adlai

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THANK YOU CARDINAL!!!! I LOVE YOU!!!!!

#10
elisfanclub

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i was having a "boot failure" when booting up to a hard drive that ONLY had OS X installed. i was NOT dual booting, and trying to get just OS X installed. my boot failure problems led me here to this post which helped alot. read below to learn my experience with the following:

boot with install DVD, hit F8 to get the prompt, and type -s to start in single mode.

when it boots to command prompt, type fdisk -e /dev/rdisk0

I am assuming you only have 1 hard drive. If you have more then one, then it could be /dev/rdisk1 and so on. You will get fdisk prompt. then type "show". Output will look like:

fdisk: 1> print
Disk: /dev/rdisk0 geometry: 24321/255/63 [390721968 sectors]
Offset: 0 Signature: 0xAA55
Starting Ending
#: id cyl hd sec - cyl hd sec [ start - size]
------------------------------------------------------------------------
*1: AF 0 1 1 - 1023 254 63 [ 63 - 390721905] HFS+
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

See the * before partition 1? That means it is active, ie, bios will try to boot from it. If you don't see a *, there is no partition set to active, and you won't boot. To set a partition to active, type:

flag 1 (or whatever partition number it is, likely 1)

Then type quit to save changes and exit. type reboot to reboot, remove the DVD and you should be booting into OSX.

Maybe what you will see instead will look scrambled and it won't see an HFS+ partition. I think this happened to me at one point while I was trying to install. Then try this (but you will have to reinstall OSX after that):

fdisk -i /dev/rdisk0 (this will reinitialize MBR, just in case)
fdisk -a hfs /dev/rdisk0 (this will make one HFS+ partition that takes the whole disk)

then make this partition active, as described at start of this post.

Reboot from DVD, install OSX into the partition you see (don't erase it, just install into it), and you should be able to boot from hard drive. If you can't, do step 1 again to make sure install program didn't make it inactive again.

I'm sure there are many far more user friendly ways to do this, but I found it easier to just use what was provided already on install DVD.


i followed this information to the T and it worked great! i just had a few problems and i'll explain them so you all can hopefully understand it better.

when i ran the "fdisk -e /dev/rdisk0" command, it returned the 4 rows like he said, but all of them were zeros and none of them had stars next to them. so, i went down to the next step and ran these two lines:

fdisk -i /dev/rdisk0
fdisk -a hfs /dev/rdisk0

it seemed to work, but instead of the 1st partition section having numbers and all that, the 1st and 2nd rows had numbers. the 1st one said something like "darwin boot" and the 2nd was "HFS".

i tried to install from the DVD but it wasn't finding any drives to install on to. on the screen when it asks you to pick a denstination drive for the install, there weren't any drives to select. the box was empty.

so, i loaded up Disk Utility (Menu Bar -> Utilities -> Disk Utility) and erased the drive. then i went back to the installer, selected the drive that i just erased and installed it successfully.

after the install, it restarted, and it BOOTED UP!!! i couldn't believe it. so i restarted with the DVD in the drive, hit F8 at the prompt, and ran "fdisk -e /dev/rdisk0" and it returned everything perfectly. there were 4 rows and the first one was HFS with a star next to it, and all the rest were zeros. somehow, in the process of erasing the drive with Disk Utility, it set everything straight. i don't quite get it, but it worked.

#11
viper92677

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I found that by entering the Disk Utility before installing OSX and clicking on your disk, then click partition, change it to 1 and apply the changes and it corrects the boot problem, I see this as being the easiest way to install it and make it boot.





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