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zozimos

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How do i modify Ubuntu install to use safe graphics (Intel) to boot up instead of AMD graphics.

Ubuntu Safe Graphics Install On 2011 Macbook Pro Completes But Does Not Restart.

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Dr. Klahn

This may not be possible ... at least, not if what is desired is "Boot with the on-board graphics, then switch over to using the AMD add-in card once linux is up."

On most systems the BIOS allows only one video adapter to be active at boot time.  Usually the BIOS option is something like "Video adapter" with selections of "Auto", "On-board," "Add-in."  If "Auto" is chosen it will prefer an add-in card if one is present.

Selecting "On-board" would cause linux to boot with the on-board graphics, but it will probably also disable the add-in card so that it can't be used once the operating system is up and running.

Fiddling the grub default boot command line to disable the AMD adapter at boot time will probably have the same effect.
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ASKER

Thanks for responding and apologies for being confusing, but this MacBook has two graphics, the Intel and AMD.  The AMD for the 2011 was somehow defective and  i cannot boot up MacOS anymore so i decided to make a linux box with the intent of using the Intel.  When i start running the Ubuntu install GRUB shows:
install Ubuntu
Install Ubuntu safe graphics
OEM install
The only option that will run at all is the safe graphics option.  The safe graphics install steps through and presents a desktop that gives the option to either Install Ubuntu or Try Ubuntu.   If i select 'Try Ubuntu' the graphics work perfectly for me.  I looked to see it was Intel graphics doing the work.  At this point, Ubuntu has not been written to disk.  To have it written onto disk, i need to go back and choose 'Install Ubuntu'.  It completes and tells me to restart.  When i restart i get the same blank screen i get when i try the first GRUB option 'install Ubuntu' rather than 'install Ubuntu safe graphics'.  I need to make some modification which would allow the Intel graphics used when i did the 'try Ubuntu' but as you said, that may not be possible.  I was hoping there would be some way to add to GRUB an option to start up in safe graphics.


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ASKER

I just put in the install disk again and this permits me to run Ubuntu directly from the disk before writing to the disk.   Display is fine.  Next step would be to actually install, writing to the disk followed by a restart.  What i need to know is when writing the system to the disk is finished but before the restart if i could go into terminal and do something so that after restart Ubuntu would use the same graphics  it used when i was running Ubuntu off the install cd.  Currently after restart it will try to use the defective AMD graphics and fail.
The OS gets the HW information from the BIOS/EFI as applicable and as noted by Dr. Klahn.

The OS does not have the luxury of choosing.

If the card is bad, disable it as was pointed out by Dr. Klahn.
Potentially, disabling the add-on card may get your Mac to boot again.

Seems odd, though if the graphics card works when you boot into Linux, the issue is not with the graphics card but potentially your OS was corrupted and much depends on what you are looking to do.
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ASKER

Actually it seems the graphics card does not boot in linux.  The graphic card works when linux set up to run off the install disk.  While Ubuntu is running off the install disk i am given the option of now installing onto the SSD after which i am to restart.   When the system attempts to actually boot up from the SSD after restart, i get only a black screen.  When Ubuntu was running off the .iso i looked to see it was Intel graphics.  What i need to have done is have Ubuntu boot up with Intel graphics instead of trying to use the AMD graphics where there is a known problem.

A black screen with a login prompt?

The software choices you made, may gave defaulted to a text mode.
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ASKER

Thanks.  Well there was one white dash (-) about a fifth of the way down the screen.  Right now the machine is running off the .iso dvd and is using the Intel.  I will now install onto dvd and restart and see if anything accepts a login.
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ASKER

After install, and attempt to restart there is just the black screen with a - somewhere, not a login.  The screen turns gray for a while, then back to black with the fan or something in high gear and left side of machine significantly warmer than rest of machine.  In the install process once the files have been written to disk, i can then go back and make changes before i restart.  It is at this time i thought maybe i could put something in GRUB to direct system to boot in safe graphics mode. No?
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ASKER

How do i disable the AMD?
ASKER CERTIFIED SOLUTION
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arnold
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ASKER

Big thanks to all!  I'm pretty sure Arnold pointed to my perfect solution, namely 'Send in your Mac' :-)   I did notice Ubuntu was supposed to run without any modifications.  "inux Support – Getting Linux running on this MacBook Pro is a nightmare. Normally involves complicated boot arguments to bypass the AMD Radeon GPU. Guess what, now that it is not there anymore, Ubuntu Linux (and others) boot up natively with no modifications what so ever. "
Actually my first attempt it did run perfectly as the article says.  I then made the imbecilic  choice to see if MacOS would run, which it did perfectly for four whole days.  After that i could not get Ubuntu running again, but it's well worth $89 to get this machine working again especially after hearing about the screen cracking problems current machines are having.
*************************ba**************************************
Meanwhile i chose to mail in to Real Mac Mods and got my 2011 back working perfectly!
BIG thanks, mil gracias and all the other good stuff.