Correct way to build partitions for reinstall

[Cyon]

Hi Gents,

I've been looking for sometime now the correct procedure to remove all partitions on a USB in preparation to create a Mavericks bootable USB. I have found on a few forums that the best way is to erase the disk in Disk Utility but to pick Master Boot Record and FAT which will force overwriting of all partitions on the storage device but it doesn't seem to work for me, as i can still the volume "Base OSX Installer" (a version of El Cap OSX i tried to put on the same USB yesterday) which tells me its not delete all partitions.

As well as attempting a clean reinstall on my MacBook Pro (2012) I am trying to troubleshoot why i get string of Kernel Panics, even when removing the physical HDD, and just trying to boot off my original DVD. I have tried PRAM reset and tested both sticks of 4GB RAM, same thing happens.

So now i have a totally wiped 750GB Sata HDD, with all partitions wiped (including EFI), and i cannot get to the installer screen with my Mavericks disc in teh drive. I just keep getting this panic. So i attempted to download El Capitan installer to create a bootable USB and it tells me the installer cannot be verified and may be corrupt. I'm going round in circles, all i want to do is get ANY version of OSX back on my machine!

Any help appreciated

Thanks
Cyon

 

[JohnDS]

Erase the drive and format it as Apple Extended Format (Journalled) with GUID partition map. Mac cannot boot from a FAT drive.

 

[MacUser2525]

I do think that machine is new enough to do internet recovery, Command + Option + R held down at boot if my memory serves me well are the keys held down at boot needed for that.

 

[jbarley]

And if the Internet Recovery doesn't work for you then I'd suspect a hardware fault (the most often cause of kernel panics), bad or poorly seated memory etc.

 

[Cyon]

Guys thank you for all your responses... but i just want to clarify:

John - i am aware that Mac cannot boot from MBR, the question was how to remove all partitions (including EFI) from a device. I know there are various Terminal and windows commands to do this but was looking for a quick, tried and tested method. Anyhow not important as i can use DISKPART from windows CMD prompt and do it that way.

MacUser2525 - Yes it is, however because i have completely obliterated the HDD has the recovery data needed to begin the initial recovery not been removed as well or is internet update a firmware thing, or part of the OSX installer tools?

jbarley - i have tried booting swapping out the 2 sticks of ram. Surely its too coincidental for both sticks to have gone wrong at exactly the same time, no?

The problem only occurs when i have the physical OSX disc in the drive and try to boot off it. I get teh computer needs to restart error message. When booting from a USB, it gets to the installer just fine but then tells me the copy of EL Cap i'm trying to install from is corrupt

 

[MacUser2525]

MacUser2525 - Yes it is, however because i have completely obliterated the HDD has the recovery data needed to begin the initial recovery not been removed as well or is internet update a firmware thing, or part of the OSX installer tools?

It loads from the firmware so is available at all times to the machine that has it, only installs the OS that was loaded at time of sale though.

 

[KALLT]

When you erase a disk with Disk Utility, you have to make sure that you select the drive and not one of its volumes. The erase function in Disk Utility works on both. When you erase just the volume, then the previous GPT labels remain intact. Erasing the whole drive will destroy the partition table and re-initialise the drive with a new one.

I do not think that there is a way, with diskutil at least, to erase a drive without re-initialising it with a new partition table. I think that zeroing out can do this, if I am reading the manual correctly, but I am not sure. This command takes some time to complete though. The command would be this (where ‘diskX’ is to be replaced with the drive you want to delete):

diskutil zerodisk diskX

diskutil does have a command for erasing the drive and re-initialising it with free space instead of a partition, which would also be a desirable result:

diskutil erasedisk free %noformat% diskX

If the partition table is GPT, then you can destroy it with this command:

sudo gpt destroy diskX

 

[Cyon]

Thanks for the tip KALLT. I used the commands and it did indeed kill the EFI on the HDD as well as the bootable USB. I then proceeded to reinstall using the recovery mode, which looked promising. It connected to the interwebs, downloaded OSX but it was taking an age, so left it on over night.

Came back in the morning and it seemed to have downloaded almost everything apart from additional components because of an issue with the internet connection. I clicked to retry the download for additional components, and its been doing that for near on 9 hours. The blue bar is full but nothing else happened so i restarted.

Now i get the same, "your computer needs to be restarted" screen again! LOL
I will try again one more time using a cable connection to the modem and post back findings. Thanks for all your help so far.