Unable to boot a once bootable system (mach-0 error)

[eshea]

hi there,
been running a fully functioning hackintosh for about a year and a half now, built to almost the exact same specs as the guide featured on Nofilmschool (http://nofilmschool.com/build-a-hackintosh/).

It's always run fine but just this morning it's started refusing to boot properly. I've always had to have the iBoot disc inserted to get it to the drive selection screen (from which i can choose either macosx or windows), however, it now takes it a very long time to get to this screen, throwing up error messages along the way:

EBIOS read error : Device timeout
Block 0x85cc Sectors 0

this appears about 5 times and eventually the disc selection screen appears. However selecting the Macosx partition causes a message to flash up very quickly before returning to the disc selection:

Mach-o file has bad magic number

Does anyone know why this would suddenly start happening and if it can be fixed? Any help appreciated.

 

[Devataa]

same problem, no idea what it means. Though I am sure it has to do with the boot loader

 

[totenkopf4]

eshea

If no hardware or software updates have bee applied to the hack then it could be that you boot volume needs to have a fsck done to it

this is a disk check like windows

You will need to get the rBoot CD from the downloads section and boot from it - this will take you to a command like prompt

You will see statement pop out on the screen regarding running a FSCK - file system check

Do the fsck in read only mode this will tell you if you have problems.
If errors show up then you will need to mount the drive from Read Only to R/W mode.

This is what the second command is - once this has been done then run the first command several times untill no errors occour.

Type reboot -RTN - the system shutdown and reboot - remove the rBoot CD - you may want to install the iBoot and boot from that CD - using the command line switchs -v -f
to see if the desktop gets up then restart w/o these switchs.

If you are unfamiliar w the internal workings of the Mackintosh world I found the following websites

and videos should be helpful.

But before you do this please look for some YOUtube vids under the name deanwrayUK
of these shortcuts.

His vid on Best Practice - http://www.youtube.com/watch?v=aZl1Gv3J7bg
His vid on Basic Overview http://www.youtube.com/watch?v=SIOJB3EVHaw
His vid on Bootloader flags http://www.youtube.com/watch?v=RDw3RhLWAjE

his youtube channel
http://www.youtube.com/user/deanwrayUK?feature=mhee

iBoot and Multibeast - TonyMacx86 guide
http://tonymacx86.blogspot.com/2010/04/ ... -x-on.html

Mac OSC 10.6.8 update - and Update Helper for 155 Sandy Bridge
http://tonymacx86.blogspot.com/2011/06/ ... pdate.html
http://tonymacx86.blogspot.com/2011/07/ ... -1068.html

TonyMac listing of alternative sources for information you may find usefull
http://www.tonymacx86.com/viewtopic.php?f=7&t=2130

TonyMac listing of supported video cards that you may find usefull
http://www.tonymacx86.com/wiki/index.ph ... d_Database

Please perform a Google search for this
" How to use Multibeast: a comprehensive guide of Multibeast options " - remove quotes
you will see several links related to Multibeast that will help you with this utility.

Something usefull about command line switchs one needs to know !
http://www.ihackintosh.com/2009/05/boot ... ootloader/

Board index » The Build » Snow Leopard Installation » 10.6 Desktop Support
http://www.tonymacx86.com/viewtopic.php?f=3&t=9541

Installation Troubleshooting Tips & General Recommendations
http://www.tonymacx86.com/viewtopic.php?f=3&t=9541
http://www.tonymacx86.com/wiki/index.ph ... leshooting

Some information on the BootX (Apple) process or what happens when you press that power button.
http://en.wikipedia.org/wiki/BootX_(Apple)