can't boot into elementary OS after pram reset on mac

Straitsfan

I apologize for my ignorance, but i'm new to EOS/Linux. And i thought i'd post here, I haven't had any response on another forum specifcially for EOS.



I had to reset the PRAM on my MB Pro the other day. I had EOS installed, and it would automatically boot to it (still hadn't figured out how to get the GRUB loader). I would have to hold down the option key to get the choice to boot El Capitan.



Anyway, after the reset it automatically boots into OS X. I thought i had erased EOS but when I attached the USB stick in order to reinstall it, it noted that EOS was already on the machine. I didn't install and took a look at GPARTED, and sure enough there it was, with the swap file and everything. In OS Disk Utility it showed the mac partition and the other partition for EOS, but was called 'unidentified.' 



So to my mind there has to be a way to be able to boot into EOS, but I don't know how to do this. Can someone help me out here? If you need more info let me know.



Here's what I can tell you so far after some replies:



I just turned on the mac after inserting the usb stick with EOS on it (i think its an iso file). When I hold down the option key I get either the mac partition or the usb stick (which is called EFI boot). I choose that one, and now I'm looking at the GNU Grub screen, with the the choices to 



Try elementary OS without installing

Install Elementary OS

OEM install (for manufacturers)

Check disc for errors



There's no rescue here (which i've been advised to try) obviously. So if I choose install, which I think is what you mean, then I get the welcome screen with a language choice



Then when I click continue I get the preparing to install elementary; i click continue with a choice to download updates while installing and one to download third party software for graphics and wi-fi hardware, etc. I don't choose either and just click continue.



Then I get the installation type window. at the the top oft he window there is a message saying that EOS is already install the computer.



I choose the "something else" option, rather than erased the disk, or encrypt the new elementary installation for security, or the use the LVM with the new elementary installation.



Then I get the installation type with all the the partitions on the SSD:



/dev/sda1 efi

/dev/sda2 hfs+ (the mac partition]

/dev/sda3 hfs+ (mac recovery partition or disk)

/dev/sda4 hfs+ (another mac recovery disk)

/dev/sda5 ext4 (the EOS partition)



There is also the linx swap file



There is also "device for boot loader installation" with the name of the SSD in the mac



There are no mount points for any of these partitions, if that makes any difference.



If a cancel the install I get the desktop, and when I open gparted it shows all the partitions, but the only one that has a flag is the EFI System Partition. none of the other partitions have any flags, and I'm not sure of that means anything.

mobile

Did you figure this out? I'm not sure the exact role NVRAM/PRAM has on booting the system on a MB, but I've helped a friend with a similar issue on his MB.

The easiest solution would be to "Try EOS without installing" or "Install" so that you can get shell. From there I would migrate/backup my filesystem to the OSx partition or an external source before reinstall EOS. Another method you could try is reinstalling grub, I'm assuming grub was installed on the sda5 partition and not the "device for bootloader installation"?

To be honest there are other "easier" ways to approach the problem, but this is by far the most straightforward I can think of-- anything else would involve 'rescue or recovery' which can all be done from the live image you have, but I'm not certain it will be that easy to alter the boot configuration on your MB.

Good luck.