thr3ads.net - CentOS - [CentOS] Fwd: 8.2.2004 Quick recovery and fix for unbootable machines with rescue disk [Aug 2020]

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Alan McRae

2020-Aug-02 02:21 UTC

[CentOS] 8.2.2004 Quick recovery and fix for unbootable machines

This is a quick recovery and fix for the machines rendered unbootable 
after the grub2/shim yum update.

It is written for CentOS 8.2.2004 but similar should work for any CentOS 
8 or 7 as long as you get the correct shim file,
that is, the one from the latest installation media.

I am running on an x86_64 architecture (see uname -i). Please use the 
correct shim file for your architecture
(shim-<arch>-15-11.el8.<arch>.rpm)

I have tested this by breaking a machine and then recovering it. It 
works for me.

I hope someone finds it useful. Let me know.

Regards
Alan

HOW TO BOOT AN UNBOOTABLE MACHINE
================================
1) Download a copy of rEFind. This is a UEFI boot manager. Burn it to a 
USB key.

# wget -O refind.zip 
http://sourceforge.net/projects/refind/files/0.12.0/refind-flashdrive-0.12.0.zip/download
# unzip refind.zip
# cd refind-flashdrive-0.12.0
# dd if=refind-flashdrive-0.12.0.img bs=4096 of=/dev/sdX (sdX is the 
device for your USB key, this will be erased, use the whole device use 
sdX not sdX1)
1800+0 records in
1800+0 records out
7372800 bytes (7.4 MB, 7.0 MiB) copied, 0.980893 s, 7.5 MB/s

2) Turn off secureboot in your UEFI hardware.

3) Boot the USB key. You should get a colourful screen with icons and a 
filename below.

Use the left/right arrow keys to select the correct grubx64.efi.
Hit space to boot.

Your usual grub menu should appear and the system should boot normally.

HOW TO FIX THE PROBLEM
====================
1) We need to downgrade the shim package. Now your system is running get 
an older copy of the correct shim package for your architecture
from the CentOS installation media (e.g. 
CentOS-8.2.2004-x86_64-dvd1.iso) and install it.

# mount CentOS-8.2.2004-x86_64-dvd1.iso /mnt
# cd /mnt/BaseOS/Packages
# cp shim-x64-15-11.el8.x86_64.rpm /root
# cd /root
# umount /mnt

OR

Get the package from a CentOS mirror:

# cd /root
# wget 
http://ucmirror.canterbury.ac.nz/linux/CentOS/8.2.2004/BaseOS/x86_64/os/Packages/shim-x64-15-11.el8.x86_64.rpm

2) We can now reinstall the older shim package using yum. This will 
downgrade the package to the working version.

# yum install shim-x64-15-11.el8.x86_64.rpm

Last metadata expiration check: 2:11:11 ago on Sun 02 Aug 2020 11:31:06 
NZST.
Dependencies resolved.

===================================================================================================================================================================================
?Package Architecture Version
Repository???????????????????????????????????? Size
===================================================================================================================================================================================Downgrading:
 ?shim-x64 x86_64 15-11.el8 
@commandline????????????????????????????????? 647 k

Transaction Summary
===================================================================================================================================================================================Downgrade?
1 Package

Total size: 647 k
Is this ok [y/N]: y
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
 ? Preparing : 1/1
 ? Downgrading????? : shim-x64-15-11.el8.x86_64 1/2
 ? Cleanup????????? : shim-x64-15-13.el8.x86_64 2/2
 ? Verifying??????? : shim-x64-15-11.el8.x86_64 1/2
 ? Verifying??????? : shim-x64-15-13.el8.x86_64 2/2
Installed products updated.

Downgraded:
shim-x64-15-11.el8.x86_64

Complete!

3) Your system should now boot normally.

4) add "exclude=shim*" to /etc/yum.conf to prevent the broken one
being
reinstalled.? You should now be able to run 'yum update'. Remove the 
exclude= when a proper fix becomes available.

Robert Heller

2020-Aug-02 03:47 UTC

head link

[CentOS] 8.2.2004 Quick recovery and fix for unbootable machines

Question:  I have a CentOS 7 VPS.  I have not yet had this problem -- I have 
not yet done an update since this problem showed up.  Will this problem affect 
my server?  *I* don't have access to the bare metal -- it is a cloud VPS I
am
renting.

At Sun, 2 Aug 2020 14:21:58 +1200 Alan McRae <amcrae at island42.net>, 
CentOS mailing list <centos at centos.org> wrote:
> 
> This is a quick recovery and fix for the machines rendered unbootable 
> after the grub2/shim yum update.
> 
> It is written for CentOS 8.2.2004 but similar should work for any CentOS 
> 8 or 7 as long as you get the correct shim file,
> that is, the one from the latest installation media.
> 
> I am running on an x86_64 architecture (see uname -i). Please use the 
> correct shim file for your architecture
(shim-<arch>-15-11.el8.<arch>.rpm)
> 
> I have tested this by breaking a machine and then recovering it. It 
> works for me.
> 
> I hope someone finds it useful. Let me know.
> 
> Regards
> Alan
> 
> HOW TO BOOT AN UNBOOTABLE MACHINE
> ================================> 
> 1) Download a copy of rEFind. This is a UEFI boot manager. Burn it to a 
> USB key.
> 
> # wget -O refind.zip 
>
http://sourceforge.net/projects/refind/files/0.12.0/refind-flashdrive-0.12.0.zip/download
> # unzip refind.zip
> # cd refind-flashdrive-0.12.0
> # dd if=refind-flashdrive-0.12.0.img bs=4096 of=/dev/sdX (sdX is the 
> device for your USB key, this will be erased, use the whole device use 
> sdX not sdX1)
> 1800+0 records in
> 1800+0 records out
> 7372800 bytes (7.4 MB, 7.0 MiB) copied, 0.980893 s, 7.5 MB/s
> 
> 2) Turn off secureboot in your UEFI hardware.
> 
> 3) Boot the USB key. You should get a colourful screen with icons and a 
> filename below.
> 
> Use the left/right arrow keys to select the correct grubx64.efi.
> Hit space to boot.
> 
> Your usual grub menu should appear and the system should boot normally.
> 
> HOW TO FIX THE PROBLEM
> ====================> 
> 1) We need to downgrade the shim package. Now your system is running get 
> an older copy of the correct shim package for your architecture
> from the CentOS installation media (e.g. 
> CentOS-8.2.2004-x86_64-dvd1.iso) and install it.
> 
> # mount CentOS-8.2.2004-x86_64-dvd1.iso /mnt
> # cd /mnt/BaseOS/Packages
> # cp shim-x64-15-11.el8.x86_64.rpm /root
> # cd /root
> # umount /mnt
> 
> OR
> 
> Get the package from a CentOS mirror:
> 
> # cd /root
> # wget 
>
http://ucmirror.canterbury.ac.nz/linux/CentOS/8.2.2004/BaseOS/x86_64/os/Packages/shim-x64-15-11.el8.x86_64.rpm
> 
> 2) We can now reinstall the older shim package using yum. This will 
> downgrade the package to the working version.
> 
> # yum install shim-x64-15-11.el8.x86_64.rpm
> 
> Last metadata expiration check: 2:11:11 ago on Sun 02 Aug 2020 11:31:06 
> NZST.
> Dependencies resolved.
> 
>
===================================================================================================================================================================================>
????Package Architecture Version
>
Repository????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
Size
>
===================================================================================================================================================================================>
Downgrading:
>  ????shim-x64 x86_64 15-11.el8 
>
@commandline????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????
647 k
> 
> Transaction Summary
>
===================================================================================================================================================================================>
Downgrade???? 1 Package
> 
> Total size: 647 k
> Is this ok [y/N]: y
> Downloading Packages:
> Running transaction check
> Transaction check succeeded.
> Running transaction test
> Transaction test succeeded.
> Running transaction
>  ???? Preparing : 1/1
>  ???? Downgrading???????????????????? : shim-x64-15-11.el8.x86_64 1/2
>  ???? Cleanup???????????????????????????????????? :
shim-x64-15-13.el8.x86_64 2/2
>  ???? Verifying???????????????????????????? : shim-x64-15-11.el8.x86_64 1/2
>  ???? Verifying???????????????????????????? : shim-x64-15-13.el8.x86_64 2/2
> Installed products updated.
> 
> Downgraded:
> shim-x64-15-11.el8.x86_64
> 
> Complete!
> 
> 3) Your system should now boot normally.
> 
> 4) add "exclude=shim*" to /etc/yum.conf to prevent the broken one
being
> reinstalled.???? You should now be able to run 'yum update'. Remove
the
> exclude= when a proper fix becomes available.
> 
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
> 
> 
-- 
Robert Heller             -- Cell: 413-658-7953 GV: 978-633-5364
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services

Kay Schenk

2020-Aug-02 20:04 UTC

head link

[CentOS] Fwd: 8.2.2004 Quick recovery and fix for unbootable machines

Hello all--
These instructions are somewhat OK but my messed up box is the only one
I've got basically to help with this problem.

Where can we find "correction" instructions using a "rescue"
CD or flash
drive? I understand RedHat provided detailed instructions to supported
customers.

Thanks.

_______________________
Sent from MzK's phone.

---------- Forwarded message ---------
From: Alan McRae via CentOS <centos at centos.org>
Date: Sat, Aug 1, 2020, 19:22
Subject: [CentOS] 8.2.2004 Quick recovery and fix for unbootable machines
To: CentOS mailing list <centos at centos.org>


This is a quick recovery and fix for the machines rendered unbootable
after the grub2/shim yum update.

It is written for CentOS 8.2.2004 but similar should work for any CentOS
8 or 7 as long as you get the correct shim file,
that is, the one from the latest installation media.

I am running on an x86_64 architecture (see uname -i). Please use the
correct shim file for your architecture
(shim-<arch>-15-11.el8.<arch>.rpm)

I have tested this by breaking a machine and then recovering it. It
works for me.

I hope someone finds it useful. Let me know.

Regards
Alan

HOW TO BOOT AN UNBOOTABLE MACHINE
================================
1) Download a copy of rEFind. This is a UEFI boot manager. Burn it to a
USB key.

# wget -O refind.zip
http://sourceforge.net/projects/refind/files/0.12.0/refind-flashdrive-0.12.0.zip/download
# unzip refind.zip
# cd refind-flashdrive-0.12.0
# dd if=refind-flashdrive-0.12.0.img bs=4096 of=/dev/sdX (sdX is the
device for your USB key, this will be erased, use the whole device use
sdX not sdX1)
1800+0 records in
1800+0 records out
7372800 bytes (7.4 MB, 7.0 MiB) copied, 0.980893 s, 7.5 MB/s

2) Turn off secureboot in your UEFI hardware.

3) Boot the USB key. You should get a colourful screen with icons and a
filename below.

Use the left/right arrow keys to select the correct grubx64.efi.
Hit space to boot.

Your usual grub menu should appear and the system should boot normally.

HOW TO FIX THE PROBLEM
====================
1) We need to downgrade the shim package. Now your system is running get
an older copy of the correct shim package for your architecture
from the CentOS installation media (e.g.
CentOS-8.2.2004-x86_64-dvd1.iso) and install it.

# mount CentOS-8.2.2004-x86_64-dvd1.iso /mnt
# cd /mnt/BaseOS/Packages
# cp shim-x64-15-11.el8.x86_64.rpm /root
# cd /root
# umount /mnt

OR

Get the package from a CentOS mirror:

# cd /root
# wget
http://ucmirror.canterbury.ac.nz/linux/CentOS/8.2.2004/BaseOS/x86_64/os/Packages/shim-x64-15-11.el8.x86_64.rpm

2) We can now reinstall the older shim package using yum. This will
downgrade the package to the working version.

# yum install shim-x64-15-11.el8.x86_64.rpm

Last metadata expiration check: 2:11:11 ago on Sun 02 Aug 2020 11:31:06
NZST.
Dependencies resolved.

===================================================================================================================================================================================
Package Architecture Version
Repository                                     Size
===================================================================================================================================================================================Downgrading:
  shim-x64 x86_64 15-11.el8
@commandline                                  647 k

Transaction Summary
===================================================================================================================================================================================Downgrade
1 Package

Total size: 647 k
Is this ok [y/N]: y
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
   Preparing : 1/1
   Downgrading      : shim-x64-15-11.el8.x86_64 1/2
   Cleanup          : shim-x64-15-13.el8.x86_64 2/2
   Verifying        : shim-x64-15-11.el8.x86_64 1/2
   Verifying        : shim-x64-15-13.el8.x86_64 2/2
Installed products updated.

Downgraded:
shim-x64-15-11.el8.x86_64

Complete!

3) Your system should now boot normally.

4) add "exclude=shim*" to /etc/yum.conf to prevent the broken one
being
reinstalled.  You should now be able to run 'yum update'. Remove the
exclude= when a proper fix becomes available.

_______________________________________________
CentOS mailing list
CentOS at centos.org
https://lists.centos.org/mailman/listinfo/centos

Gregory P. Ennis

2020-Aug-02 21:06 UTC

head link

[CentOS] Fwd: 8.2.2004 Quick recovery and fix for unbootable machines with rescue disk

Hello all--
These instructions are somewhat OK but my messed up box is the only one
I've got basically to help with this problem.

Where can we find "correction" instructions using a "rescue"
CD or flash
drive? I understand RedHat provided detailed instructions to supported
customers.

Thanks.

_______________________
Sent from MzK's phone.

---------- Forwarded message ---------
From: Alan McRae via CentOS <centos at centos.org>
Date: Sat, Aug 1, 2020, 19:22
Subject: [CentOS] 8.2.2004 Quick recovery and fix for unbootable machines
To: CentOS mailing list <centos at centos.org>


This is a quick recovery and fix for the machines rendered unbootable
after the grub2/shim yum update.

It is written for CentOS 8.2.2004 but similar should work for any CentOS
8 or 7 as long as you get the correct shim file,
that is, the one from the latest installation media.

I am running on an x86_64 architecture (see uname -i). Please use the
correct shim file for your architecture
(shim-<arch>-15-11.el8.<arch>.rpm)

I have tested this by breaking a machine and then recovering it. It
works for me.

I hope someone finds it useful. Let me know.

Regards
Alan

HOW TO BOOT AN UNBOOTABLE MACHINE
================================
1) Download a copy of rEFind. This is a UEFI boot manager. Burn it to a
USB key.

# wget -O refind.zip
http://sourceforge.net/projects/refind/files/0.12.0/refind-flashdrive-0.12.0.zip/download
# unzip refind.zip
# cd refind-flashdrive-0.12.0
# dd if=refind-flashdrive-0.12.0.img bs=4096 of=/dev/sdX (sdX is the
device for your USB key, this will be erased, use the whole device use
sdX not sdX1)
1800+0 records in
1800+0 records out
7372800 bytes (7.4 MB, 7.0 MiB) copied, 0.980893 s, 7.5 MB/s

2) Turn off secureboot in your UEFI hardware.

3) Boot the USB key. You should get a colourful screen with icons and a
filename below.

Use the left/right arrow keys to select the correct grubx64.efi.
Hit space to boot.

Your usual grub menu should appear and the system should boot normally.

HOW TO FIX THE PROBLEM
====================
1) We need to downgrade the shim package. Now your system is running get
an older copy of the correct shim package for your architecture
from the CentOS installation media (e.g.
CentOS-8.2.2004-x86_64-dvd1.iso) and install it.

# mount CentOS-8.2.2004-x86_64-dvd1.iso /mnt
# cd /mnt/BaseOS/Packages
# cp shim-x64-15-11.el8.x86_64.rpm /root
# cd /root
# umount /mnt

OR

Get the package from a CentOS mirror:

# cd /root
# wget
http://ucmirror.canterbury.ac.nz/linux/CentOS/8.2.2004/BaseOS/x86_64/os/Packages/shim-x64-15-11.el8.x86_64.rpm

2) We can now reinstall the older shim package using yum. This will
downgrade the package to the working version.

# yum install shim-x64-15-11.el8.x86_64.rpm

Last metadata expiration check: 2:11:11 ago on Sun 02 Aug 2020 11:31:06
NZST.
Dependencies resolved.

==================================================================================================================================================================================
Package Architecture Version
Repository                                     Size
==================================================================================================================================================================================Downgrading:
  shim-x64 x86_64 15-11.el8
@commandline                                  647 k

Transaction Summary
==================================================================================================================================================================================Downgrade
1 Package

Total size: 647 k
Is this ok [y/N]: y
Downloading Packages:
Running transaction check
Transaction check succeeded.
Running transaction test
Transaction test succeeded.
Running transaction
   Preparing : 1/1
   Downgrading      : shim-x64-15-11.el8.x86_64 1/2
   Cleanup          : shim-x64-15-13.el8.x86_64 2/2
   Verifying        : shim-x64-15-11.el8.x86_64 1/2
   Verifying        : shim-x64-15-13.el8.x86_64 2/2
Installed products updated.

Downgraded:
shim-x64-15-11.el8.x86_64

Complete!

3) Your system should now boot normally.

4) add "exclude=shim*" to /etc/yum.conf to prevent the broken one
being
reinstalled.  You should now be able to run 'yum update'. Remove the
exclude= when a proper fix becomes available.

_______________________________________________

Dear List,

I have had 6 of these problems and am on my way to the office to fix two more.

Here is what I did with an installation disc along with the advise from the
posts of Johny
Hughes.  So far this has been easy to do and has worked every time.  Make sure
your system
is connected to the network, and know your gateway address and a reasonable ip
address of
the machine for your network.

#1. Boot to tine Install Disc and pick "Recovery Mode"

#2. You will be given several options of recover Pick #1 to Continue

#3. Use the 'chroot /mnt/sysimage' command to get into  your system

#4. Activate  your network

Find the device name you are going to use

ip link
gives you the name as in 'enp3s0' as the device

ip link set dev enpo3s0 up
activates the network card

ip address add 10.0.0.67/24 dev enp3s0
sets the card's address to 10.0.0.67 with a subnet mask of 255.255.255.0

ip route add default via 10.0.0.124
sets the gateway for your machine to 10.0.0.124

#5. Make sure you have an active domain name service

cd /etc/

vim resolv.conf

Edit the appropriate value of 
nameserver 10.0.0.124

(in my case the nameserver and gateway were the same machine)

#6. Use of Yum
yum clean all
This necessary so that you can make sure you have the latest listings

yum install shim

For Centos 7 you want shim-x64-15-8.el7.x86_64 which Johnny Hughes just released
today.

When this  is installed  you will also install mokutil-15-8.el7.x86_64

#7. Exit out of recovery mode, and reboot.

This has worked for me every time.

Thanks to everyone's advice on this list and all the good work done by the
Centos Team!!!!

Greg Ennis

Mark LaPierre

2020-Aug-03 03:02 UTC

head link

[CentOS] 8.2.2004 Quick recovery and fix for unbootable machines

On 8/1/20 10:21 PM, Alan McRae via CentOS wrote:> This is a quick recovery and fix for the machines rendered unbootable 
> after the grub2/shim yum update.
> 
> It is written for CentOS 8.2.2004 but similar should work for any CentOS 
> 8 or 7 as long as you get the correct shim file,
> that is, the one from the latest installation media.
> 
> I am running on an x86_64 architecture (see uname -i). Please use the 
> correct shim file for your architecture
(shim-<arch>-15-11.el8.<arch>.rpm)
> 
> I have tested this by breaking a machine and then recovering it. It 
> works for me.
> 
> I hope someone finds it useful. Let me know.
> 
> Regards
> Alan
> 
> HOW TO BOOT AN UNBOOTABLE MACHINE
> ================================> 
> 1) Download a copy of rEFind. This is a UEFI boot manager. Burn it to a 
> USB key.
> 
> # wget -O refind.zip 
>
http://sourceforge.net/projects/refind/files/0.12.0/refind-flashdrive-0.12.0.zip/download
> 
> # unzip refind.zip
> # cd refind-flashdrive-0.12.0
> # dd if=refind-flashdrive-0.12.0.img bs=4096 of=/dev/sdX (sdX is the 
> device for your USB key, this will be erased, use the whole device use 
> sdX not sdX1)
> 1800+0 records in
> 1800+0 records out
> 7372800 bytes (7.4 MB, 7.0 MiB) copied, 0.980893 s, 7.5 MB/s
> 
> 2) Turn off secureboot in your UEFI hardware.
> 
> 3) Boot the USB key. You should get a colourful screen with icons and a 
> filename below.
> 
> Use the left/right arrow keys to select the correct grubx64.efi.
> Hit space to boot.
> 
> Your usual grub menu should appear and the system should boot normally.
> 
> HOW TO FIX THE PROBLEM
> ====================> 
> 1) We need to downgrade the shim package. Now your system is running get 
> an older copy of the correct shim package for your architecture
> from the CentOS installation media (e.g. 
> CentOS-8.2.2004-x86_64-dvd1.iso) and install it.
> 
> # mount CentOS-8.2.2004-x86_64-dvd1.iso /mnt
> # cd /mnt/BaseOS/Packages
> # cp shim-x64-15-11.el8.x86_64.rpm /root
> # cd /root
> # umount /mnt
> 
> OR
> 
> Get the package from a CentOS mirror:
> 
> # cd /root
> # wget 
>
http://ucmirror.canterbury.ac.nz/linux/CentOS/8.2.2004/BaseOS/x86_64/os/Packages/shim-x64-15-11.el8.x86_64.rpm
> 
> 
> 2) We can now reinstall the older shim package using yum. This will 
> downgrade the package to the working version.
> 
> # yum install shim-x64-15-11.el8.x86_64.rpm
> 
> Last metadata expiration check: 2:11:11 ago on Sun 02 Aug 2020 11:31:06 
> NZST.
> Dependencies resolved.
> 
>
====================================================================================================================================================================================
> 
>  ?Package Architecture Version 
> Repository???????????????????????????????????? Size
>
====================================================================================================================================================================================
> 
> Downgrading:
>  ?shim-x64 x86_64 15-11.el8 
> @commandline????????????????????????????????? 647 k
> 
> Transaction Summary
>
====================================================================================================================================================================================
> 
> Downgrade? 1 Package
> 
> Total size: 647 k
> Is this ok [y/N]: y
> Downloading Packages:
> Running transaction check
> Transaction check succeeded.
> Running transaction test
> Transaction test succeeded.
> Running transaction
>  ? Preparing : 1/1
>  ? Downgrading????? : shim-x64-15-11.el8.x86_64 1/2
>  ? Cleanup????????? : shim-x64-15-13.el8.x86_64 2/2
>  ? Verifying??????? : shim-x64-15-11.el8.x86_64 1/2
>  ? Verifying??????? : shim-x64-15-13.el8.x86_64 2/2
> Installed products updated.
> 
> Downgraded:
> shim-x64-15-11.el8.x86_64
> 
> Complete!
> 
> 3) Your system should now boot normally.
> 
> 4) add "exclude=shim*" to /etc/yum.conf to prevent the broken one
being
> reinstalled.? You should now be able to run 'yum update'. Remove
the
> exclude= when a proper fix becomes available.
> 
Thank you for your apparently well researched and written article.  The 
only problem I see with it is that it's going to be really hard for a 
CentOS user with a tanked system to read unless that user has access to 
some other system where this can be read.

-- 
     _
    ?v?
   /(_)\
    ^ ^  Mark LaPierre
Registered Linux user No #267004
https://linuxcounter.net/
****

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