Please help!!! Mbr failed - cannot boot!

Discussion in 'macOS' started by faria0884, Oct 19, 2011.

  1. faria0884 macrumors newbie

    Joined:
    Oct 19, 2011
    #1
    :eek:


    I am so glad I found this forum. So here is what happened:

    I was running OSX Lion, and wanted to install Linux as a dual boot. I used BootCamp to set up a partition, but chose to "install the os later". Then I installed REFIT (not sure why I just read online that I should). Next, I reboot my mbp and booted from a fedor live cd. After restarting my mbp shows "no bootable device" message. I read that this is due to MBR but I have no clue how to fix it.

    Here's what I've done so far:

    1) Booted from the Ultimate Super Boot CD or whatever it is called - there I tried various partitioning tools, boot tools, but nothing works, it all freezes. I tried using Boot2Disk to boot from my HD but it froze as well. Kon-Boot doesn't do much either.

    2) When I insert my SnowLeopard DVD it doesn't even recognize it...I still get the "no bootable device" message after holding option/cmd

    3) I read I should try gptsync, but have no clue howto use it...do they make an iso image of it?

    Im basically clueless by now. Can someone please help. I've been going at it for 4 days now. Thanks.
     
  2. cal6n macrumors 68000

    cal6n

    Joined:
    Jul 25, 2004
    Location:
    Gloucester, UK
    #2
    1. Download the latest ubuntu live CD .iso and burn it to disc.

    2. Insert into Mac and boot. At the chime, hold down the "c" key. Select "Try ubuntu" or whatever option corresponds to that. Do not install ubuntu.

    3. Open GParted and use it to examine your hard disc and the partitions. It should look similar to (but not the same as) the image here. Make sure the boot flag is on your EFI partition and make sure you apply your changes or whatever.

    4. Quit your live ubuntu session and restart and it should boot to OS X.

    5. If it doesn't, post back here. You'll probably need to do a reinstall from scratch. I hope you've got a time machine backup...
     

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  3. faria0884 thread starter macrumors newbie

    Joined:
    Oct 19, 2011
    #3
    Ok I will follow your steps and let you know how this is coming along. If gparted doesn't work I won't mind reinstalling from scratch. My only issue is HOW CAN I REINSTALL FROM SCRATCH "if" when I put in my snow leopard dvd I don't even have an option to boot from the DVD and it doesn't read the DVD at all. Weird because when I put in my Fedora 15 live CD it boots from that but doesn't pick up the OSX.

    Ok I will try gparted and let you know what's going on. In the case that it doesn't work I hope there is a way to reinstall the os given the issue that I have above.

    Thanks...
     
  4. cal6n macrumors 68000

    cal6n

    Joined:
    Jul 25, 2004
    Location:
    Gloucester, UK
    #4
    Your Lion recovery partition stops you from booting the Snow Leopard installer.

    If you can't repair your EFI boot flag using GParted, you will at least be able to erase each partition manually and then format the whole disc to FAT32. You'll then be able to boot the Snow Leopard installer and proceed as if there was a new hard drive in there.

    This ought to work. I managed to maintain my linux dualboot while rolling my Mac back from Lion to Snow Leopard using only gparted, IIRC.
     
  5. faria0884 thread starter macrumors newbie

    Joined:
    Oct 19, 2011
    #5
    UNFORTUNATELY gparted didn't work. My mbp didn't even recognize GPARTED there. What's going on with that? It only recognizes Fedora 15 livecd and the Super Bootable CD or whatever it's called. It won't boot osx dvd or gparted - I downloaded gparted iso and try booting from that - didn't work.

    So what do I do now?

    PLEASE HELP!!!
     
  6. cal6n, Oct 19, 2011
    Last edited: Oct 19, 2011

    cal6n macrumors 68000

    cal6n

    Joined:
    Jul 25, 2004
    Location:
    Gloucester, UK
    #6
    Try running it from an ubuntu live CD.

    Get it here:

    http://www.ubuntu.com/download/ubuntu/download

    (you'll probably want the 64 bit version, unless your Mac is quite old) and follow the instructions in part 3.

    ----------

    When you are at the ubuntu desktop, you should see a stack of tiles up the left hand side. If you click on the top one, you should get a search field and you can then search for "gparted" and proceed as before.

    I don't have a live CD to check but, if they don't include gparted any more, there ought to be something with similar functionality. Maybe called disk utility or somesuch...
     
  7. faria0884 thread starter macrumors newbie

    Joined:
    Oct 19, 2011
    #7
    Ok I'll give ubuntu a shot.... probably will take a while to download with my slow internet haha. IF that fails, what is my other option?

    I should also mention that I have a second HD that has a clone of my os x prior to doing all the bootcamp and linux....but when I swap the HDs it still doesn't see a "bootable drive". This is way too weird for me. I hope you understand this.
     
  8. faria0884 thread starter macrumors newbie

    Joined:
    Oct 19, 2011
    #8
    I TRIED UBUNTU....UNFORTUNATELY IT DOES NOT WORK!

    My macbook pro will not read the cd at all! Again this is weird. IT only reads fedora - maybe that's because that's the last os that I booted from?

    Anyways....WHAT DO I DO NOW? PLEASE HELP
     
  9. cal6n macrumors 68000

    cal6n

    Joined:
    Jul 25, 2004
    Location:
    Gloucester, UK
    #9
    I've just looked at your original post.

    In order to see your bootable drives, you need to hold down only the option key at boot time, not option+cmd.

    In order to boot from a CD you should hold down the "C" key at boot time.

    In order to restore Lion you should hold down the "cmd+R" keys at boot time.

    If these shortcuts aren't working, then you have a real problem.

    You could try resetting your SMC and PRAM, but if you can't boot an ubuntu live CD (or your cloned HD) after that, then I have no more advice for you, except to take it to the Apple store for repair.
     

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