[SOLVED] Slackware current installed does not boot on UEFI computer

jamasoo · 04-22-2021, 11:18 AM

Hello!

I managed to install Slackware current on a dual boot computer with UEFI. The problem is that it goes straight into windows. I have to use the DVD iso and huge.s root=/dev/sda7 rdinit= ro in the initial prompt to boot linux.I have created a partition with gdisk and disabled UEFI to legacy and disabled secure boot. Lastly here is my partition table:

https://lh3.googleusercontent.com/-1...-no?authuser=0

I have no clue as to why this is happening so could you please enlighten me? thanks.

arubin · 04-22-2021, 12:41 PM

I suppose the answer to why does it go straight to Windows is 'why wouldn't it?'

It's a long time since I set up dual booting on my PC but at that time, nine years ago early days of EFI I found it quite challenging. There should be more help online now. You will need to set up a boot manager (my favoured one is reFINnd, but GRUB and eLILO are other possibilities) edit the comfiguration for that and get your BIOS to choose the boot manager as default.

Alan

hazel · 04-22-2021, 12:49 PM

Did you run /usr/sbin/eliloconfig? This should set up elilo to boot correctly.

brobr · 04-22-2021, 12:53 PM

Quote:

Originally Posted by jamasoo

Hello!

..I have ... disabled UEFI to legacy ..

Is this correct? I guess you do not want 'legacy'; in my memory that allows for lilo booting; that's not what you aim to do..

ReFracture · 04-22-2021, 01:09 PM

Last time I did a dual boot on a single drive in legacy mode I found grub to be pretty easy to setup, so I'd probably use that since you've disabled UEFI.

jamasoo · 04-22-2021, 01:39 PM

Quote:

Originally Posted by arubin

I suppose the answer to why does it go straight to Windows is 'why wouldn't it?'

It's a long time since I set up dual booting on my PC but at that time, nine years ago early days of EFI I found it quite challenging. There should be more help online now. You will need to set up a boot manager (my favoured one is reFINnd, but GRUB and eLILO are other possibilities) edit the comfiguration for that and get your BIOS to choose the boot manager as default.

Alan

I will give a try tomorrow... thanks

jamasoo · 04-22-2021, 01:50 PM

Quote:

Originally Posted by hazel

Did you run /usr/sbin/eliloconfig? This should set up elilo to boot correctly.

Will do it first thing in the morning. I appreciated.

jamasoo · 04-22-2021, 02:02 PM

Quote:

Originally Posted by brobr

Is this correct? I guess you do not want 'legacy'; in my memory that allows for lilo booting; that's not what you aim to do..

That is correct, i just got confused, thanks for pointing out this. I forgot legacy was to allow lilo to boot. Years ago i did an install where i had to do just that, go figure...

enorbet · 04-22-2021, 03:50 PM

However enabling CSM (legacy boot) does not disable UEFI boot. so that shouldn't be a problem while Secure Boot definitely can be a problem (not only for some Linux distros but even for Windows <read up on bitlocker>) . All you need do to boot Slackware in EFI mode, assuming you allowed eliloconfig to complete, is to enter BIOS/UEFI and adjust in the "Boot" section for default selection - OR - hit whatever keystroke gets you to Boot Order menu upon initial startup and select which you wish to boot. FWIW I always multiboot and like rEFInd as default which I have setup to display several Linux installs and old Windows as well, all on one bootloader.

colorpurple21859 · 04-22-2021, 07:19 PM

your disk label is dos not gpt. A gpt type disk doesn't have an extended partition and there is no efi partition. Even though you have a uefi computer windows was installed in legacy mode. It would be better to have slackware boot in the same mode as windows, legacy mode. Boot into slackware install lilo. If for some reason your not able to install lilo because you booted in uefi mode, install grub with this

Code:

grub-install --target=i386-pc /dev/sda
grub-mkconfig -o /boot/grub/grub.cfg

Once booted to slackware in legacy mode then if you prefer install lilo.

If you want to install slackware in uefi mode, the 100Mb partition will need to be formatted as fat32 and flagged as esp/efi, not sure if it needs to be on a primary partition or not.

RadicalDreamer · 04-22-2021, 07:50 PM

The easy way to dual boot Windows and Slackware is with refind. https://slackbuilds.org/repository/14.2/system/refind/

Do you see this?

Code:

bash-5.1# fdisk -l | grep EFI

Code:

bash-5.1# mount | grep efi
/dev/sda1 on /boot/efi type vfat (rw)

Code:

bash-5.1$ ls
Boot  Microsoft  Slackware  refind  tools
bash-5.1$ pwd
/boot/efi/EFI

As you can see the efi partition is mounted and it has Microsoft folder, a Slackware folder (eliloconfig), and refind folder. If Windows is using efi then that partition already exists. It just needs elilo or grub installed on it via the Slackware folder.

My Slackware EFI folder contains.

Code:

/boot/efi/EFI/Slackware
bash-5.1# ls
elilo.conf  elilo.efi  initrd.gz  vmlinuz

Install elilo once and just copy the new vmlinuz and initrd.gz into the folder after each kernel update.

I also recommend using UUID to identify your partitions in fstab and when creating a initrd.gz. A couple of years ago Windows 10 added partitions throwing the partition numbering off so this prevents a mess. Can find the UUID of your partitions with

Code:

bash-5.1# blkid

fstab should look like

Code:

#/dev/sda2
UUID=X-X-X-X      /                ext4        defaults         1   1

Then make initrd.gz with something like

Code:

mkinitrd -c -k X.XX.X -m ext4 -r "UUID=X-X-X-X" -u -o /boot/initrd.gz

Also Windows occasionally likes to set itself as the preferred bootloader. You can esc in bios and load refind and fix boot order with efibootmgr in Slackware with 0000 being whatever boot manager you want to use:

Code:

efibootmgr -o 0000

enorbet · 04-23-2021, 10:20 AM

Just FTR it is possible and reasonable to convert MBR to GPT non-destructively and it's actually easier in Linux. I forget the actuall command syntax but I've done it a few times just refreshing memory with numerous sites such as this one --- https://www.explorelinux.com/convert...-gpt-on-linux/

jamasoo · 04-23-2021, 03:08 PM

Quote:

Originally Posted by colorpurple21859

your disk label is dos not gpt. A gpt type disk doesn't have an extended partition and there is no efi partition. Even though you have a uefi computer windows was installed in legacy mode. It would be better to have slackware boot in the same mode as windows, legacy mode. Boot into slackware install lilo. If for some reason your not able to install lilo because you booted in uefi mode, install grub with this

Code:

grub-install --target=i386-pc /dev/sda
grub-mkconfig -o /boot/grub/grub.cfg

Once booted to slackware in legacy mode then if you prefer install lilo.

If you want to install slackware in uefi mode, the 100Mb partition will need to be formatted as fat32 and flagged as esp/efi, not sure if it needs to be on a primary partition or not.

It worked! After a fresh reinstall i chose lilo (elilo did not show up this time as in the previous install) and in legacy mode all worked out fine. Amazing response from you guys.

Thanks for all the help.

hazel · 04-24-2021, 04:53 AM

Mark it as solved then.

enorbet · 04-24-2021, 08:42 AM

I know it's working to OPs satisfaction but just FTR, in order to get the prompt to skip lilo and go to elilo on Slackware Install one has to either have CSM disabled or hit the Boot Order key to select the UEFI entry for whatever device you have the installer on since it can boot several ways but will only offer elilo if it boots via UEFI.