BigSur installed on virtual box does not allow me to install virtual guest addition

[fxPlus]

I have installed BigSur on a virtual machine. Now I'm trying to install guest additions on this BigSur virtualized environment. I'm following this guideline: (LINK TO UPDATE IN A DAY) but the command to access recovery mode gives me operation not permitted:

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sudo nvram "recovery-boot-mode=unused"
nvram: Error setting variable: - "recovery-boot-mode": (iokit/common) not permitted.

There is a way to access recovery mode from a virtual box machine maybe simulating

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cmd+r

inserting? Or there is another way to install guest additions?
Thank you.

p.s I cannot link URLs and images because I'm a new user here. I'll update the topic as soon as possible.
Note that I have the iso from where I installed the operating system. I thought retrying to boot from a live cd would be the solution but I was not able to perform this attempt and I got only a primitive shell where I'm able to do nothing from there.

[scottgus1]

Start the guest from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the guest from within the guest OS if possible. If not possible, close the Virtualbox window for the guest with the Power Off option set.

Right-click the guest in the main Virtualbox window's guest list, choose Show Log. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab.

[fxPlus]

Start the guest from full normal shutdown, not save-state. Run until you see the problem happen, then shut down the guest from within the guest OS if possible. If not possible, close the Virtualbox window for the guest with the Power Off option set.

Right-click the guest in the main Virtualbox window's guest list, choose Show Log. Save the far left tab's log, zip it, and post the zip file, using the forum's Upload Attachment tab.

sorry but I don't understand what this action should be useful for. My problem regards guest additions which to be installed on osx, requires csrutil to be disabled and I cannot perform this action until I don't access recovery mode. I was asking for a method to access recovery mode since with bigsur that command from terminal seems has been disabled.

Update: I managed to disable some protection but the installation of virtual box guest additions still fails because from BigSur the disk is not writable anymore. There is any solution to this?

[granada29]

@fxPlus

I confirm your problem in attempting to install the Guest Additions into a macOS 11 (Big Sur) guest.

I don't think that disabling SIP on the guest would be anything other than a workaround. During installation of the Guest Additions, ideally you would be prompted in the guests 'Security & Privacy' preferences panel to allow the installation of the kexts. The fact that this doesn't happen is a bug and maybe you could file a bug-report at https://www.virtualbox.org/wiki/Bugtracker

I have never really needed the GA's on a macOS guest, and use the native file/screen sharing instead. Screen sharing also gives you bi-directional copy and paste. I enable screen and file sharing in the guests System Preferences/Sharing, which then makes the guest visible to my host. You can reduce screen clutter on your host by minimizing the VM window while you are using screen sharing.

Even when installed (e.g. on Sierra, High Sierra etc), the macOS GA's do not provide window resizing. To set a reasonable guest display size you need to use the methods described in https://www.virtualbox.org/manual/UserM ... efividmode

[erwin9]

Result of my tries to install Guest Additions on Big Sur 11.0.1:

• This cannot work unless to disable the SSV (Signed System Volume), which requires first to disable the FileVault.
• After that, there is no way to reactivate SSV nor FileVault, and you remain unsigned for life, which means not sure you can get further updates from Apple

Why ? There are several things to that ..:

1. First, you have to get the kext-consent on the Oracle Developer ID, which for some reason on my Catalina upgraded to Big Sur image is not there:

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   spctl kext-consent add VB5E2TV963

   (in Recovery mode .. that doesn't work in a normal session)
2. Second, it appears you need to enable the Guest Additions install package to write to /System/Library/Extensions/ (because I presume this is what is needed for the kext mechanism):

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   sudo mount -uw /
   sudo chown :admin /System/Library/Extensions/
   sudo chmod 775 /System/Library/Extensions/

3. But Big Sur now makes the whole / filesystem not only "read-ony", but also locked with SSV ... so the above does not work (operation not permitted / denied on chown and chmod).
4. And disabling SIP (in Recovery mode again)

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   csrutil disable

   is not sufficient for allowing that, there remains the

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   csrutil authenticated-root disable

   thing to do, which requires first to disable FileVault, else that second disabling command simply fails.
5. Once you've done that, you can then mount the volume in write mode to modify it and install GA, and then go on (crossing fingers) to bless it

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   sudo bless --folder /[mountpath]/System/Library/CoreServices --bootefi --create-snapshot

   to get to something bootable again
6. But from there SSV and FileVault cannot be reactivated

The whole problem, besides the surprise that 1) is not known by Apple and we have to force it in, is 2) = why does GA install require to write to /System/Library/Extensions/ ?
I guess we can't have the kext mechanism anymore in Big Sur ... or let me know if I am wrong ??

=> Can VBoxDarwinAdditions.pkg switch to System extensions rather than kext ?


Some references:
https://eclecticlight.co/2020/06/25/big ... rotection/
https://stackoverflow.com/questions/416 ... ne-as-host
https://apple.stackexchange.com/questio ... in-big-sur
https://support.apple.com/en-us/HT210999
https://developer.apple.com/documentati ... extensions

[fxPlus]

Result of my tries to install Guest Additions on Big Sur 11.0.1:
[*]First, you have to get the kext-consent on the Oracle Developer ID, which for some reason on my Catalina upgraded to Big Sur image is not there:

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spctl kext-consent add VB5E2TV963

(in Recovery mode .. that doesn't work in a normal session)
[*]Second, it appears you need to enable the Guest Additions install package to write to /System/Library/Extensions/ (because I presume this is what is needed for the kext mechanism):

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sudo mount -uw /

Hi and thanks for your answer.
I did

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 csrutl authenticated-root disabled

(there is a command to check the status too?)
but unfortunately I think that BigSur does not allow to:

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sudo mount -uw /

Anyway I'll make another attempt and I'll notice here. You can check why by this guy who explains it well: https://twitter.com/ebadtweet/status/12 ... 3900971012