Cannot write to efivars
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I have booted from an Ubuntu 17.10.1 live DVD on a 2011 MacBook Pro (in EFI mode) and I'm trying to issue the following command to disable the discrete GPU:
printf "x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
And I am getting this error no matter what I do:
bash: printf: write error: Invalid argument
I know this question has been asked and answered before, but I have already verified that the efivars filesystem is mounted rw and I have removed the immutability flag with chattr -i.
I can touch the file to create it, and I can delete it with rm, but any attempt to actually write data to the file at all results in a write error, whether I use echo, printf, or try to cp or mv the file from another writeable directory. Nothing seems to work.
I have also tried this in Debian and that didn't work either.
Those that are familiar with the MacBook Pro GPU bug might suggest that I boot into single user mode and issue an nvram command from there, but the laptop does not have an operating system installed to boot into (and I can't install macOS because of the GPU).
Is there no way to write to efivars anymore?
command-line kernel permissions uefi
asked Feb 9 at 16:57
Wes Sayeed
1062
add a comment |
up vote
1
down vote
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I have booted from an Ubuntu 17.10.1 live DVD on a 2011 MacBook Pro (in EFI mode) and I'm trying to issue the following command to disable the discrete GPU:
printf "x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
And I am getting this error no matter what I do:
bash: printf: write error: Invalid argument
I know this question has been asked and answered before, but I have already verified that the efivars filesystem is mounted rw and I have removed the immutability flag with chattr -i.
I can touch the file to create it, and I can delete it with rm, but any attempt to actually write data to the file at all results in a write error, whether I use echo, printf, or try to cp or mv the file from another writeable directory. Nothing seems to work.
I have also tried this in Debian and that didn't work either.
Those that are familiar with the MacBook Pro GPU bug might suggest that I boot into single user mode and issue an nvram command from there, but the laptop does not have an operating system installed to boot into (and I can't install macOS because of the GPU).
Is there no way to write to efivars anymore?
command-line kernel permissions uefi
asked Feb 9 at 16:57
Wes Sayeed
1062
Did you try booting using cmd-option-r and booting to the MacOS / internet recovery option? From there, open a terminal (it's in one of the pull downs on the first page) and you can use Apple's "nvram" command to write to the NVRAM? I haven't used this for GPU issues but did while trying to disabled the Apple "bong" on bootup after a bare metal Ubuntu install to a macbook pro7,1.
– randy
May 10 at 19:09
add a comment |
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I have booted from an Ubuntu 17.10.1 live DVD on a 2011 MacBook Pro (in EFI mode) and I'm trying to issue the following command to disable the discrete GPU:
printf "x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
And I am getting this error no matter what I do:
bash: printf: write error: Invalid argument
I know this question has been asked and answered before, but I have already verified that the efivars filesystem is mounted rw and I have removed the immutability flag with chattr -i.
I can touch the file to create it, and I can delete it with rm, but any attempt to actually write data to the file at all results in a write error, whether I use echo, printf, or try to cp or mv the file from another writeable directory. Nothing seems to work.
I have also tried this in Debian and that didn't work either.
Those that are familiar with the MacBook Pro GPU bug might suggest that I boot into single user mode and issue an nvram command from there, but the laptop does not have an operating system installed to boot into (and I can't install macOS because of the GPU).
Is there no way to write to efivars anymore?
command-line kernel permissions uefi
asked Feb 9 at 16:57
Wes Sayeed
1062
I have booted from an Ubuntu 17.10.1 live DVD on a 2011 MacBook Pro (in EFI mode) and I'm trying to issue the following command to disable the discrete GPU:
printf "x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
And I am getting this error no matter what I do:
bash: printf: write error: Invalid argument
I know this question has been asked and answered before, but I have already verified that the efivars filesystem is mounted rw and I have removed the immutability flag with chattr -i.
I can touch the file to create it, and I can delete it with rm, but any attempt to actually write data to the file at all results in a write error, whether I use echo, printf, or try to cp or mv the file from another writeable directory. Nothing seems to work.
I have also tried this in Debian and that didn't work either.
Those that are familiar with the MacBook Pro GPU bug might suggest that I boot into single user mode and issue an nvram command from there, but the laptop does not have an operating system installed to boot into (and I can't install macOS because of the GPU).
Is there no way to write to efivars anymore?
command-line kernel permissions uefi
command-line kernel permissions uefi
asked Feb 9 at 16:57
Wes Sayeed
1062
asked Feb 9 at 16:57
Wes Sayeed
1062
asked Feb 9 at 16:57
Wes Sayeed
1062
asked Feb 9 at 16:57
Wes Sayeed
1062
asked Feb 9 at 16:57
Wes Sayeed
1062
1062
Did you try booting using cmd-option-r and booting to the MacOS / internet recovery option? From there, open a terminal (it's in one of the pull downs on the first page) and you can use Apple's "nvram" command to write to the NVRAM? I haven't used this for GPU issues but did while trying to disabled the Apple "bong" on bootup after a bare metal Ubuntu install to a macbook pro7,1.
– randy
May 10 at 19:09
add a comment |
Did you try booting using cmd-option-r and booting to the MacOS / internet recovery option? From there, open a terminal (it's in one of the pull downs on the first page) and you can use Apple's "nvram" command to write to the NVRAM? I haven't used this for GPU issues but did while trying to disabled the Apple "bong" on bootup after a bare metal Ubuntu install to a macbook pro7,1.
– randy
May 10 at 19:09
Did you try booting using cmd-option-r and booting to the MacOS / internet recovery option? From there, open a terminal (it's in one of the pull downs on the first page) and you can use Apple's "nvram" command to write to the NVRAM? I haven't used this for GPU issues but did while trying to disabled the Apple "bong" on bootup after a bare metal Ubuntu install to a macbook pro7,1.
– randy
May 10 at 19:09
Did you try booting using cmd-option-r and booting to the MacOS / internet recovery option? From there, open a terminal (it's in one of the pull downs on the first page) and you can use Apple's "nvram" command to write to the NVRAM? I haven't used this for GPU issues but did while trying to disabled the Apple "bong" on bootup after a bare metal Ubuntu install to a macbook pro7,1.
– randy
May 10 at 19:09
add a comment |
1 Answer
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up vote
0
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I think the command is wrong. I successfully used:
printf "x07x00x00x00x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
Found here.
Note that in some resources the backslashes are missing (leading to the same error message).
answered Dec 1 at 20:08
lumbric
2,79812141
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
0
down vote
I think the command is wrong. I successfully used:
printf "x07x00x00x00x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
Found here.
Note that in some resources the backslashes are missing (leading to the same error message).
answered Dec 1 at 20:08
lumbric
2,79812141
add a comment |
up vote
0
down vote
I think the command is wrong. I successfully used:
printf "x07x00x00x00x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
Found here.
Note that in some resources the backslashes are missing (leading to the same error message).
answered Dec 1 at 20:08
lumbric
2,79812141
add a comment |
up vote
0
down vote
up vote
0
down vote
I think the command is wrong. I successfully used:
printf "x07x00x00x00x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
Found here.
Note that in some resources the backslashes are missing (leading to the same error message).
answered Dec 1 at 20:08
lumbric
2,79812141
I think the command is wrong. I successfully used:
printf "x07x00x00x00x01x00x00x00" > /sys/firmware/efi/efivars/gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9
Found here.
Note that in some resources the backslashes are missing (leading to the same error message).
answered Dec 1 at 20:08
lumbric
2,79812141
answered Dec 1 at 20:08
lumbric
2,79812141
answered Dec 1 at 20:08
lumbric
2,79812141
answered Dec 1 at 20:08
lumbric
2,79812141
2,79812141
add a comment |
add a comment |
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Did you try booting using cmd-option-r and booting to the MacOS / internet recovery option? From there, open a terminal (it's in one of the pull downs on the first page) and you can use Apple's "nvram" command to write to the NVRAM? I haven't used this for GPU issues but did while trying to disabled the Apple "bong" on bootup after a bare metal Ubuntu install to a macbook pro7,1.
– randy
May 10 at 19:09