Does resetting NVRAM reset EFI Boot Order

bootdual-bootefinvram

I've had a Macbook Pro for a year or so now and have experimented with quite a few Linux distributions which have added and changed things in the EFI Boot Order. I am looking to clean things up. The tool efibootmgr for Linux does let me make changes and cleanup as necessary. However will resetting NVRAM reset the EFI Boot Order for me?

Best Answer

NVRAM is a standalone chip on your logic board, backed up by small battery.

EFI resides on your SSD. (hard drive)

Showing battery for the PRAM (NVRAM)

So no, resetting NVRAM will not impact EFI.

To restore EFI, you have to reinstall the OS X.

Related Solutions

Nvram boot-args to boot in target disk mode

From this (very useful!) page : http://www.cnet.com/news/how-to-manage-os-x-boot-options-with-wireless-keyboards/

I found the answer you want. And I quote:

The "boot-args" variable can be used for setting the above modes. but in addition if you need to load the system into Target Disk mode, you can do so by setting the "target-mode" PRAM variable in the following way (this will be enabled only once for the next time the system is started):
sudo nvram target-mode=1

It looks like you can't get it to do that on every boot - but you could write a startup script that waited for a minute then set that parameter again then rebooted. Note that without the delay, you would never be able to boot the machine again :)

Then if you ever did want to start the machine not in Target Disk Mode, you would simply kill the startup script while it was waiting for the minute.

Dual boot Ubuntu 14.04 on a MacBook Pro

Ubuntu has instructions for most macbook pro's. Depending on which version of the macbook pro you have you may not need rEFInd:

https://help.ubuntu.com/community/MacBookPro

Best Answer

Related Solutions

Nvram boot-args to boot in target disk mode

Dual boot Ubuntu 14.04 on a MacBook Pro

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