Hi - Have had 22.04 installed for a few months in dual-boot partition alongside Win8.1. Grub was working just fine. Ubuntu was installed from a bootable USB.
Updater advised that I upgrade to 24.04.1. It was a long process. Felt great that it appeared to go well, except that default OS was now Ubuntu. I wanted to default to Win8 again. I made the change in grub file and updated. But Win8 would not boot - Bad shim signature.
I had reinstalled 22.04 a few weeks after the first install (because I forgot the pwd) and also ended up not accessing Win but somehow managed to fix it with boot-repair. I don’t know exactly what I did.
This time boot-repair is not helping. I have read hundreds of posts and articles seeing as I want to understand what I am doing and not simply follow a given repair recipe. But now I am running out of time and patience and need that quick fix. I have uploaded a diagnostics file to pastebin at https://paste.ubuntu.com/p/qWKM4hpqHT/. I suspect that the problem lies in a small reserved partition which appears to be serving no purpose – nothing in it. I can see it in Gparted and would past the image if I could only see how to attach it – ah yes, there is an upload icon. This is probably a simple solution which I just cannot figure out after a few days of learning and trying.
Thanks
Note that Windows updates make Windows first in boot order. Windows may also update UEFI resetting and turn on fast startup which prevents grub from booting Windows. You should always be able to boot both Windows & Ubuntu from UEFI boot menu, but Acer requires you to set “trust” on Ubuntu entry. And grub install or major update will reset grub/shim to be first in boot order. Shimx64.efi required if UEFI secure boot on, lwhich may be turned on with Windows or UEFI updates. Usually you can reset boot order in UEFI with efibootmgr or with UEFI system settings, boot tab, not UEFI boot menu.
Running boot repair with the Create BootInfo Summary option without making any changes would probably be the best step to take. When you are booted into Ubuntu, take a look at the /boot/grub/grub.cfg file and check to see if there is a windows entry. If so, post it here. Do you see a Microsoft directory when you run: sudo ls /boot/efi/EFI?
Hi @yancek - am struggling with what I suspect is markup/markdown formatting. Tried putting this extract from grub.cfg in blockquotes …???
BEGIN /etc/grub.d/30_os-prober
menuentry ‘Windows Boot Manager (on /dev/sda2)’ --class windows --class os $menuentry_id_option ‘osprober-efi-BA32-C38A’ {
insmod part_gpt
insmod fat
set root=‘hd0,gpt2’
if [ x$feature_platform_search_hint = xy ]; then
search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt2 --hint-efi=hd0,gpt2 --hint-baremetal=ahci0,gpt2 BA32-C38A
else
search --no-floppy --fs-uuid --set=root BA32-C38A
fi
chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}
There is no EFI subdirectory inside the /efi directory ls: cannot access ‘/boot/efi/EFI’: No such file or directory
I am attaching the summary txt file.
Boot files: /efi/Boot/bkpbootx64.efi /efi/Boot/bootx64.efi
/efi/Boot/fbx64.efi /efi/Boot/grubx64.efi
/efi/Boot/mmx64.efi /efi/ubuntu/grubx64.efi
/efi/ubuntu/mmx64.efi /efi/ubuntu/shimx64.efi
/efi/ubuntu/grub.cfg /efi/Microsoft/Boot/bootmgfw.efi
/efi/Microsoft/Boot/bootmgr.efi
/efi/OEM/Boot/bootmgfw.efi /efi/OEM/Boot/bootmgr.efi
I don’t think these are in the Ubuntu partition - in the disk root.
Thanks @oldfred - OK just seen discourse tip explaining how to blockquote and and respond to several responses in my single reply - will get there in due course. My response a bit jumbled I’m afraid - perhaps I am oldnev …
Note that Windows updates make Windows first in boot order. Windows may also update UEFI resetting and turn on fast startup which prevents grub from booting Windows. You should always be able to boot both Windows & Ubuntu from UEFI boot menu, but Acer requires you to set “trust” on Ubuntu entry. And grub install or major update will reset grub/shim to be first in boot order. Shimx64.efi required if UEFI secure boot on, lwhich may be turned on with Windows or UEFI updates. Usually you can reset boot order in UEFI with efibootmgr or with UEFI system settings, boot tab, not UEFI boot menu.
Before I follow up your response in more detail, I need to make sure I understand it.
Does “UEFI” in your response mean “UEFI/BIOS”?
Certainly seems to be some non-cooperation between Win and Linux over boot order!
I will see what efibootmgr is - ah - a command: Here is it’s output:
BIOS, although still frequently in use, is the older name for the PC firmware, which is active before any OS boots. Often described as software that enables hardware to run
UEFI is simply a new iteration of firmware with more features, more choices and more confusing acronyms
Anyway, back to booting Windows
In your screenshot of Boot Priority, when you select Windows Boot Manager, does it boot successfully?
Sorta worked that UEFI/BIOS thing out with all the reading that I have been doing. Thus my question. Thanks.
Your question:
In your screenshot of Boot Priority, when you select Windows Boot Manager, does it boot successfully?
No. There is no way I can boot into Win. Tried changing BIOS boot order too.
What concerns me is the small unknown partition marked Microsoft reserved partition. (see screenshot in earlier post.) Only 128M. Appears to contain no information. If it slipped in during the update, perhaps the partitions references are now incorrect. But Ubuntu still boots correctly. I don’t know if that small partition was there before the upgrade.
I am sure that the WinOS is still fine - all the files are still there. Just directing grub to it seems to be the problem.
BTW - when I told a developer friend (of course a Linux guy all the way) that I am now migrating to Linux, he said that “Linux is only free if your time is free”. I have spent many hours over many days with this and other Linux issues - and not been paid a cent - it has been a sweat but fun. Much of that time has been deploying small distros on old laptops - even greater fun!
The Microsoft windows ‘reserved’ partition is standard on new windows installs. So what exactly happens when you select windows from the Grub menu or from the UEFI menu in the BIOS? Do you see any warning/error messages on screen ?
If Windows Boot Manager won’t load Windows, you may need to use a Windows repair disk (although it may be difficult for Windows 8, which became unsupported in January 2023)
Boot-repair > Advanced Options > Other Options > Repair Windows Boot Files
May be worth a punt, but, more often than not, Windows utilities will be needed.
The memtest options also return bad shim signature.
Is the boot-repair summary available to you guys? It contains plenty of very interesting info which I sort of understand, but I don’t understand the recommendations at the end. I did try the recommended repair without success. It appears that I cannot attach a text file on this forum - only the full summary in a block quote - am I correct?
I might have a Win8 install disk - of sorts. Will take a look.
Good point about the repair options which I hope someone can help me with. I am loathe to try options for fear of causing even worse problems.
The option to reinstall grub has always been unticked, but running it again now, I see that it is now ticked . But this is after having just tried the memtest options, reverting to grub menu and running Ubuntu. Perhaps makes for different recommendations??
Did you by chance install off a 22.04.0 or 22.04.1 media ?
Both these images had to be withdrawn because Microsoft had accidentially leaked their secureboot master key right after they were released … if you installed from these images before they were removed from the server it could well be that you are booting with a revoked UEFI key now …
I have thought of doing that but am concerned I will cause further problems. If you think it is not too dangerous, I will give it a go. I will back out of BIOS without saving Legacy mode.
Disabling Secure Boot will not exacerbate anything.
You can always enable it again later.
Recent versions of Ubuntu and Windows 10/11 will boot with Secure Boot disabled.
I do not know about unsupported Windows 8
Best not to post Boot-Repair Summary Report, but post link it gives to the pastebin site. If when booting Windows, it must be failing & UEFI goes to next in boot you have order (Ubuntu) and then shim fails. Not sure if Windows also changed their key but if Windows 8 not updating then that is a separate issue. Do not know Windows 8.
My response a bit jumbled I’m afraid - perhaps I am oldnev 
…
