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SnakeHaveYou

macrumors newbie
Original poster
Aug 30, 2010
18
7
Hello all, i have a MacBook Air M1 with 256GB, and after modifying some NVRAM settings with Terminal, it got bricked after a reboot. In some sites, it's said that the MacBook with the M1 chipset will revert the NVRAM to the original settings after a reboot if it won't boot, some other said that you need to close the lid for 30 sec after powering off, but in my MacBook the settings remains the same, and the same boot mode with the link to fix the MacBook with the Apple Configurator 2 guide.

I don't have any other Mac device to install Apple Configurator 2, so it was imposible for me to fix it with that method.

So after that, i booted my MacBook into the startup options boot mode, selected the Options menu and using the Terminal app from the Utilities menu, i modified back the NVRAM settings to default, rebooted and it worked.

So is there any way to reset the NVRAM settings with the M1 chipset?

Using Apple Configurator 2 is the only way to fix it when macOS fails to update?

Thanks!!
 

jdb8167

macrumors 601
Nov 17, 2008
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I've only done it the same way as you did. Boot into recovery, choose Terminal from the menu. Then:

nvram -c
 

Quackers

macrumors 68000
Sep 18, 2013
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Manchester, UK
I was under the impression that there is no way/need to reset SMC or NVRAM on a M1.
I think they are reset on every boot. But I have no evidence for that :)
 

jdb8167

macrumors 601
Nov 17, 2008
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I was under the impression that there is no way/need to reset SMC or NVRAM on a M1.
I think they are reset on every boot. But I have no evidence for that :)
Like the OP I had a unbootable M1 MacBook Air after playing around with nvram settings. I admit that I didn't spend a lot of time waiting for the system to fix itself. After the initial boot failure I booted into recovery and issued the terminal command. If I ever have a problem again, I'll boot a couple of times to see if it fixes itself but I don't think I'm willing to experiment with setting bad nvram variables.
 
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jdb8167

macrumors 601
Nov 17, 2008
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There is no manual NVRAM / SMC reset for M1. That now occurs during a normal reboot.
Some of Apple's man pages are out of date for the M1 but Big Sur still has a man page that says the command nvram -c removes all nvram variables. If you run it from recovery and the terminal, you don't get an error or anything. As far as I can tell it still works and I was certainly able to make my M1 MBA unbootable with an incorrect nvram setting.
 
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Apple_Robert

Contributor
Sep 21, 2012
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In the middle of several books.
Some of Apple's man pages are out of date for the M1 but Big Sur still has a man page that says the command nvram -c removes all nvram variables. If you run it from recovery and the terminal, you don't get an error or anything. As far as I can tell it still works and I was certainly able to make my M1 MBA unbootable with an incorrect nvram setting.
Attempting to manually reset SMC etc. is a waste of time, because the M1 does not have the management controller the Intel Mac's do. That is why the process is automatic with the M1 during reboot.
 

jdb8167

macrumors 601
Nov 17, 2008
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Attempting to manually reset SMC etc. is a waste of time, because the M1 does not have the management controller the Intel Mac's do. That is why the process is automatic with the M1 during reboot.
SMC is different than nvram.
 

SnakeHaveYou

macrumors newbie
Original poster
Aug 30, 2010
18
7
As I said, both are now automated with the M1. That is a fact. The NVRAM is reset after a normal shutdown.

If you want to go into Terminal and treat the M1 as if it were an Intel reset, go ahead. I am not going to argue about it.

My MacBook didn't reset the NVRAM settings by itself. After modifying NVRAM settings, i turned it off, and after powering up, the MacBook was unbootable. After that, i turned it off pressing the power button, keep the lid close, and after that, it was unbootable.
I configured again the NVRAM from Terminal because i knew what settings i've modified, so i modified those settings again.

I was under the impression that there is no way/need to reset SMC or NVRAM on a M1.
I think they are reset on every boot. But I have no evidence for that :)

I don't know, the other setting i've modified or added is still there: AutoBoot
And i don't know if that setting is on the default NVRAM config.


I've only done it the same way as you did. Boot into recovery, choose Terminal from the menu. Then:

nvram -c

I configured again a boolean setting on the NVRAM, not with "nvram -c". With "nvram -p" the setting i've modified was still there.
 
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Mike Boreham

macrumors 68040
Aug 10, 2006
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UK
There is no manual NVRAM / SMC reset for M1. That now occurs during a normal reboot.

In your later posts you have said "after a normal shutdown", which I believe is more correct. There doesn't seem to an any definitive Apple documentation on the subject but I have seen a few places where it is said that a complete shutdown for more than 30 seconds was required, and that a reboot doesn't do it.

A confusing factor in the topic is that while it seems pretty clear that there are no NVRAM/SMC reset tools, it is still possible to change NVRAM settings eg verbose mode boot as in this thread, which doesn't say how you are supposed to unset it.
 
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Richard Tillard

macrumors member
Feb 8, 2021
40
41
I've only done it the same way as you did. Boot into recovery, choose Terminal from the menu. Then:

nvram -c
It does nothing.

The only way to do an NVRAM reset now is to do exactly a complete shutdown and then turn it on. So don't waste your time with commands like that. As the architecture changes, the actions we are used to are also changing.
 

jdb8167

macrumors 601
Nov 17, 2008
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It does nothing.

The only way to do an NVRAM reset now is to do exactly a complete shutdown and then turn it on. So don't waste your time with commands like that. As the architecture changes, the actions we are used to are also changing.
It removed the nvram variable that was preventing boot. It is possible that a complete shutdown and waiting 30 seconds does the same thing but I didn’t try that. But saying it does nothing seems incorrect.
 

SnakeHaveYou

macrumors newbie
Original poster
Aug 30, 2010
18
7
In your later posts you have said "after a normal shutdown", which I believe is more correct. There doesn't seem to an any definitive Apple documentation on the subject but I have seen a few places where it is said that a complete shutdown for more than 30 seconds was required, and that a reboot doesn't do it.

A confusing factor in the topic is that while it seems pretty clear that there are no NVRAM/SMC reset tools, it is still possible to change NVRAM settings eg verbose mode boot as in this thread, which doesn't say how you are supposed to unset it.

Well i tried to turn off the MacBook, using the power button, and keep it off for more than that, with the lid close, and after that, it was still unbootable to the OS.
I could reset the NVRAM settings not by setting to default, but by changing again the "Auto-Boot" boolean variable i've modified manually.


It does nothing.

The only way to do an NVRAM reset now is to do exactly a complete shutdown and then turn it on. So don't waste your time with commands like that. As the architecture changes, the actions we are used to are also changing.

There is an "Auto-Boot" setting, that's the variable i've modified and after that, the MacBook was unable to boot to the OS.

EDIT: "nvram -c" delete all the firmware variables:


it doesn't reset it to defaults.


I could try to modify again the "Auto-Boot" setting to test if the NVRAM settings resets after a power off, but i don't have any other Mac device to restore it if i can't enter to Terminal again.
 
Last edited:

SnakeHaveYou

macrumors newbie
Original poster
Aug 30, 2010
18
7
Imagen 12-2-21 a las 03.02.jpeg


I don't know why, but my previous post is awaiting for moderator approval, but I explained some things about my settings.
 
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jdb8167

macrumors 601
Nov 17, 2008
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View attachment 1728909

I don't know why, but my previous post is awaiting for moderator approval, but I explained some things about my settings.
There is a variable called auto-boot now and it is set to true. That was what I tried to change and it prevented my M1 MacBook Air from booting. I don't remember what I set it to but it might have been %00. Anyway, I don't recommend messing around with the nvram variables, they seem to be able to interfere with normal operation pretty severely.
 

SnakeHaveYou

macrumors newbie
Original poster
Aug 30, 2010
18
7
There is a variable called auto-boot now and it is set to true. That was what I tried to change and it prevented my M1 MacBook Air from booting. I don't remember what I set it to but it might have been %00. Anyway, I don't recommend messing around with the nvram variables, they seem to be able to interfere with normal operation pretty severely.
It was the same setting i’ve modified, “Auto-Boot” has a boolean value, the default in my MacBook is “true”, i modified to “false” because using “AutoBoot=%00” didn’t disable the power on while opening the lid, so i tried “Auto-Boot” to “false”.
But that screenshot is showing that “AutoBoot=%00” didn’t revert to its original value after a reboot o power off.
Also “Auto-Boot” and “AutoBoot” seems to be for different things or architecture, because the guides that says you can modify “AutoBoot” probably are for Intel based products.
 

Richard Tillard

macrumors member
Feb 8, 2021
40
41
EDIT: "nvram -c" delete all the firmware variables:


it doesn't reset it to defaults.


I could try to modify again the "Auto-Boot" setting to test if the NVRAM settings resets after a power off, but i don't have any other Mac device to restore it if i can't enter to Terminal again.

I hope you are able to resolve your problem. For the future, do not use any commands unless you really know what they do, because this can sometimes cause real damage to your computer.
 
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