How to do "nomodeset" booting up 7.2 installer?

TG4FOSS

New Member
May 25, 2022
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Hi all -- I'm running into a problem when installing 7.2. I can boot up from a USB stick with the installer on it, and get to the first installation screen.

At that point, if I choose "Install Proxmox VE", I see about a dozen lines of boot-up text and then the screen goes blank, with the video monitor showing the message "Input Not Supported". Web searching suggests this is most likely a video mode problem, and I should try specifying "nomodeset" on the kernel boot line -- although, apparently, even this does not always do the trick and more obscure kernel options may be needed.

So, I boot again and choose "Advanced Options". This time I boot into the installer's "Debug mode", but when I try to edit /mnt/boot/grub/grub.cfg to put "nomodeset" in the boot options, I'm told it's on a read-only file system. If I try Rescue Boot, I briefly see "ZFS rescue boot", followed by several fast-scrolling screens of boot text, and then the same "Input Not Supported" message on the monitor.

I've also tried holding down the Esc key and the Space bar while booting. No luck there either; I get back to the same initial installer screen.

More details: First, I am able to boot up and complete a 7.1 installation so this is clearly a regression, and web searches indicate it's upstream with Debian (and LOTS of people are hitting the problem) -- which means that doing a Debian-based install would just put the same brick wall in front of me (trying to install the latest Ubuntu runs into the same problem too). However, I want to install 7.2, not 7.1. Second, this is a UEFI-based boot, though I could disable that if need be.

So my questions are:

1) How do I break out of the installer's boot-up screens so that I can prevent it from trying to switch video modes?

2) Once there, what do I need to set so that my video continues to work, but also supports the Proxmox installer? (Alternatively, is there a text-based installer? And no, I don't want to do a Debian-based install, I want to do as plain and supportable a Proxmox installation as possible).
 
If you're in grub command mode, don't try to save the file, just edit the command line and continue to boot.
If you see "ZFS rescue boot" it means the system is at least partially installed. You could try a bootable usb and mount the fs rw and edit it there, but if it's not finished setup, that might cause other problems.
Try pressing C when the boot menu appears. This might help:
https://www.linuxfoundation.org/blog/classic-sysadmin-how-to-rescue-a-non-booting-grub-2-on-linux/
I'm not in grub command mode -- that's what I'm trying to get to. When I'm editing /mnt/boot/grub/grub.cfg it's because I've managed to boot up in Debug mode, and it's a case of desperation, trying to edit anything that looks like it might be related to boot up. But alas, it's not just a read-only file, it's a file on a read-only filesystem.

I suspect the zfs message is there because of the successful install of 7.1, not because of a partially successful install of 7.2.

I've been going around with this for *days*, burning up time I really should be spending on something my organization perceives as more productive. It's clearly a regression in Proxmox, it's widely reported in the Debian world, and it's causing a lot of grief for many people -- I'm surprised that Debian or one of it's big downstream distros has not addressed the problem. Proxmox makes it worse by locking you out of the usual ways of manipulating video modes when booting into the installer. I was really enthused about using Proxmox for our organization, and maybe being able to show my boss a working system that could justify a subscription. Now it looks like I might have to drop back to something else.
 
Hi all -- I'm running into a problem when installing 7.2. I can boot up from a USB stick with the installer on it, and get to the first installation screen.

At that point, if I choose "Install Proxmox VE", I see about a dozen lines of boot-up text and then the screen goes blank, with the video monitor showing the message "Input Not Supported". Web searching suggests this is most likely a video mode problem, and I should try specifying "nomodeset" on the kernel boot line -- although, apparently, even this does not always do the trick and more obscure kernel options may be needed.

So, I boot again and choose "Advanced Options". This time I boot into the installer's "Debug mode", but when I try to edit /mnt/boot/grub/grub.cfg to put "nomodeset" in the boot options, I'm told it's on a read-only file system. If I try Rescue Boot, I briefly see "ZFS rescue boot", followed by several fast-scrolling screens of boot text, and then the same "Input Not Supported" message on the monitor.

I've also tried holding down the Esc key and the Space bar while booting. No luck there either; I get back to the same initial installer screen.

More details: First, I am able to boot up and complete a 7.1 installation so this is clearly a regression, and web searches indicate it's upstream with Debian (and LOTS of people are hitting the problem) -- which means that doing a Debian-based install would just put the same brick wall in front of me (trying to install the latest Ubuntu runs into the same problem too). However, I want to install 7.2, not 7.1. Second, this is a UEFI-based boot, though I could disable that if need be.

So my questions are:

1) How do I break out of the installer's boot-up screens so that I can prevent it from trying to switch video modes?

2) Once there, what do I need to set so that my video continues to work, but also supports the Proxmox installer? (Alternatively, is there a text-based installer? And no, I don't want to do a Debian-based install, I want to do as plain and supportable a Proxmox installation as possible).

Hi all -- I'm running into a problem when installing 7.2. I can boot up from a USB stick with the installer on it, and get to the first installation screen.

At that point, if I choose "Install Proxmox VE", I see about a dozen lines of boot-up text and then the screen goes blank, with the video monitor showing the message "Input Not Supported". Web searching suggests this is most likely a video mode problem, and I should try specifying "nomodeset" on the kernel boot line -- although, apparently, even this does not always do the trick and more obscure kernel options may be needed.

So, I boot again and choose "Advanced Options". This time I boot into the installer's "Debug mode", but when I try to edit /mnt/boot/grub/grub.cfg to put "nomodeset" in the boot options, I'm told it's on a read-only file system. If I try Rescue Boot, I briefly see "ZFS rescue boot", followed by several fast-scrolling screens of boot text, and then the same "Input Not Supported" message on the monitor.

I've also tried holding down the Esc key and the Space bar while booting. No luck there either; I get back to the same initial installer screen.

More details: First, I am able to boot up and complete a 7.1 installation so this is clearly a regression, and web searches indicate it's upstream with Debian (and LOTS of people are hitting the problem) -- which means that doing a Debian-based install would just put the same brick wall in front of me (trying to install the latest Ubuntu runs into the same problem too). However, I want to install 7.2, not 7.1. Second, this is a UEFI-based boot, though I could disable that if need be.

So my questions are:

1) How do I break out of the installer's boot-up screens so that I can prevent it from trying to switch video modes?

2) Once there, what do I need to set so that my video continues to work, but also supports the Proxmox installer? (Alternatively, is there a text-based installer? And no, I don't want to do a Debian-based install, I want to do as plain and supportable a Proxmox installation as possible).
Hi,
Did you manage to solve the problem?
I'm also not able to install a 7.2 on an old HP Proliant server.
I already edited the boot line in grub and it still doesn't work.
See the video below.

https://youtu.be/ogbVz54lUKg
 
Hi,
Did you manage to solve the problem?
I'm also not able to install a 7.2 on an old HP Proliant server.
I already edited the boot line in grub and it still doesn't work.
See the video below.

https://youtu.be/ogbVz54lUKg
No Joy with 7.2. Instead I dropped back to 7.1, which works. Once installed, from the console I adjusted /etc/apt/sources.list and /etc/apt/sources.list.d/pve-enterprise.list so as to activate the no-subscription repo and deactivate the subscription repo (pve-enterprise), then did an 'apt update' and 'apt full-upgrade'. This is *supposed* to bring everything completely up to date, at least with the Debian base. Not sure if it should bring Proxmox up to 7.2. Everything seems to be working, though the servers haven't been put under stress or into production yet.
 
I wanted to say I had the same issue with an old supermicro server. I could not install 7.2, no matter what I tried to do on the grub command line to mess with video resolution. The monitor would say 'cannot display video mode.'

My solution was the same as @TG4FOSS going back to 7.1, which did work with the exact same hardware. I wonder, did something get dropped with a newer kernel, or is this a base Debian issue?
 
I got 7.2 installed on my new host by using two steps:
1) To get the first part of install going, I had to switch "quiet splash = silent" to nomodeset (press 'e' while the "install" option is selected, to get to editor)
2) That went pretty far, then failed with an error about FrameBuffer Mode failing. My resolution on that may help resolve a number of other similar issues. See here
 

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