[lug] GRUB2 Compatibility: Mostly Fedora/Ubuntu, Some BIOS/UEFI

Wed Jul 19 15:26:12 MDT 2017

A couple of shoot from the hip thoughts:

Just to make sure I understand, you've got a UEFI system running in legacy
BIOS mode which worked well for your MBR partitioned disks on older OSes
but after upgrading it's not working so well? The compatibility issues
between UEFI, MBR, BIOS, and GPT mostly come down to how the bootstrapping
process loads the kernel from a specific part of the disk. The UEFI/BIOS
issue typically comes down to motherboard firmware interaction with the OS.

I believe that legacy mode for UEFI was so it could play nice with older
OSes. It's my understanding that UEFI can still understand MBR disks (ie.
it doesn't require GPT disks like BIOS systems require MBR disks). I assume
you've attempted to disable legacy mode and tried to let it interact with
your MBR partitioned disk?

Otherwise, if it's easy (ha, famous last words), you could look at
converting your MBR disk to GPT, running your system in "native" UEFI mode
and trying to boot your newly converted GPT disk. Maybe clone your disk
before attempting that!

If those things don't help, could we see your partition table?
-Dan

On Wed, Jul 19, 2017 at 2:36 PM, <stimits at comcast.net> wrote:

> Thanks for the reply! It is appreciated.
>
> I don't think it is entirely that BIOS modes are not supported in
> Ubuntu...I think it is confused by a UEFI-capable motherboard being in BIOS
> mode. Fedora works fine this way, Ubuntu is incapable of setting up USB on
> the same system though. Though command line tools for Fedora seem to have
> some issues the installer does not. I suspect that there hasn't been much
> reason to test newer distributions with BIOS compatibility mode.
>
> Knowing any other stories about how Ubuntu and Fedora work when mixed
> together and steps required would help...but knowing this same information
> for a newer motherboard in BIOS compatibility mode would help more. I just
> don't see many posts out in the wild where boot loader setup talks about
> how it works with compatibility mode. Mostly everything assumes UEFI.
>
> From what I can tell there may be some differences between the Fedora GRUB
> boot loader and Ubuntu's version of GRUB...add this on top of the whole
> UEFI/BIOS question.
>
> ----- Original Message -----
> From: Davide Del Vento <davide.del.vento at gmail.com>
> To: Boulder (Colorado) Linux Users Group -- General Mailing List <
> lug at lug.boulder.co.us>
> Sent: Wed, 19 Jul 2017 18:35:24 -0000 (UTC)
> Subject: Re: [lug] GRUB2 Compatibility: Mostly Fedora/Ubuntu, Some
> BIOS/UEFI
> Sorry I don't have anything to tell you. I'm just responding to let you
> know that at least somebody is reading you and the mailing list isn't dead.
> I just find it strange that Ubuntu would not support BIOS modes, but what
> do I know? I still know more about LILO than GRUB....
>
> On Mon, Jul 17, 2017 at 4:19 PM, <stimits at comcast.net> wrote:
>
>> Hi,
>>
>> I'm looking for thoughts on issues which seem to be from mixing Fedora
>> and Ubuntu mixed boot environments, explained below.
>>
>> My recent adventures and success at repairing my partition resize
>> failures inspired me to rearrange partitions, delete some old data, and try
>> to modernize some of my Fedora software. Basically I am still using Fedora
>> 23, but have a working Fedora 26 install as well (there are some issues,
>> but F26 mostly works well). During my experimentation I've verified my
>> hardware works with Fedora 19, Fedora 23, Fedora 25, Fedora 26, memtest86+,
>> and Windows 7.
>>
>> Just to make a few details available ahead of time, my motherboard
>> supports UEFI, but it is in BIOS compatibility mode. Partitions on all
>> disks are all old style BIOS partitions. No UEFI is used, no GPT partition
>> is present.
>>
>> During any Fedora install the GRUB install seems to have succeeded. After
>> install I do not seem to be able to use any of the grub command line
>> manipulation programs from Fedora 26 though (Fedora 25 command line was the
>> same)...those commands demand to use UEFI files despite not being UEFI mode
>> and having no GPT partitions at all. GRUB refuses to do any command line
>> change or update; GRUB cites missing UEFI files as a reason to reject my
>> update attempts. Installation seems to understand BIOS partitions, Fedora
>> command line user space tools do not (perhaps it is detecting my
>> motherboard as UEFI even though it is in BIOS mode). I admit this is
>> probably my lack of understanding the proper tool usage for newer GRUB
>> tools, else I wouldn't be posting here. Documentation on the Internet is
>> sparse though, google searches seem to assume UEFI and there is a lack of
>> documentation on using old style BIOS mode on a UEFI-capable motherboard
>> with BIOS partitions.
>>
>> Ubuntu is far worse and has some serious issues, though I'm booting
>> through the Fedora boot loader and configuration, so perhaps it isn't all
>> the fault of Ubuntu. I believe Ubuntu does not handle BIOS style hardware
>> on a UEFI board at all well. During install (I have a separate partition
>> for Fedora 23, Fedora 26, and Ubuntu) of any Ubuntu (tried many versions,
>> old through modern) I get a large number of USB errors. If I disconnect
>> everything except keyboard and mouse I don't see those errors...I also
>> don't get a keyboard or mouse once install finishes. All of my USB devices
>> function 100% with no error or warning at any point in their existence
>> under Windows 7, Fedora 19, Fedora 23, Fedora 25, Fedora 26, and
>> memtest86+. I believe this is due to Ubuntu missing old style BIOS setup,
>> and trying to use non-existent UEFI partition layout (which would cause USB
>> to not properly load). Does anyone know of a way to tell an Ubuntu install
>> to force BIOS mode so I can test this theory (for example, a way to drop
>> into installer command line and change boot parameter)?
>>
>> I do actually need the older Ubuntu 14.04 for some software which only
>> runs on Ubuntu 14.04...I can do without it (I have for quite some time),
>> but it is a big pain and I'd like to get Ubuntu 14.04 working, or at least
>> Ubuntu 16.04 (the software partially works in 16.04).
>>
>> One additional thing I've noticed is that some of GRUB's environment
>> setup differs from Fedora's version. I may be wrong, but it seems Ubuntu
>> has modified GRUB, or else is somehow different when Ubuntu is loaded from
>> a Fedora GRUB loader instead of an Ubuntu GRUB loader. Does anyone here
>> know if there are compatibility issues or hoops to jump through to load
>> Ubuntu from a Fedora boot loader?
>>
>> Thanks!
>>
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>
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-- 
------
 Dan Mackin - http://appliedtrust.com/dan
 AppliedTrust - http://appliedtrust.com - 303.245.4516
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