Unable to select operating system in a dualbooted device. Windows 10 and Linux Mint

[languid vector]

Lenovo Thinkpad t460s
PC keeps automatically into linux mint. i dont see a grub boot menu.
typing "efibootmgr" on the terminal keeps showing that "EFI variables are not supported on this system.
how do i switch between the two OS's?

[boreal stratus]

how old is pc?

[languid vector]

About 9 years old

[boreal stratus]

probably need to reinstall linux in UEFi MODE

and turn Windows Fast Startup off, in Windows

[languid vector]

Will I still have windows?

[boreal stratus]

also check the msinfo32 app in Windows, and take note of the listed BIOS mode

[languid vector]

I did turn it off before installing Linux

I can't access windows

Only Linux mint boots up

[boreal stratus]

go to bios , turn on uefi boot

and move windows boot manager to top of boot list

gotta redo the linux install.

[languid vector]

It had both turned on, with legacy first

What option should I select

[boreal stratus]

just put to pure uefi boot

[boreal stratus]

legacy/csm off

[languid vector]

My windows was in NTFS, doesn't it mean it's on legacy

[boreal stratus]

this is why efi varables arent supported. u booted the installer in legacy (and it created a legacy install)

[boreal stratus]

it probably is

[languid vector]

So how should I fix the situation

[boreal stratus]

if not, then it would show in grub menu

[languid vector]

I selected Uefi only

[boreal stratus]

switch as i said

yes

now go to boot order list

what u find?

[languid vector]

Turned csm support off

[languid vector]

How to go to boot order list

[boreal stratus]

*csm

should show as a category no?

[languid vector]

@boreal stratus

Can you find it here

[boreal stratus]

also turn off Quick boot

[languid vector]

Done. Where's boot order

[boreal stratus]

so that should now read as:

[languid vector]

Check please sir

[boreal stratus]

• UEFI only
• UEFI first
• csm NO

ok just try save and exit/reboot (note F12)

[languid vector]

I just get boot menu now

[languid vector]

Entering the ATA HDD does nothing

[boreal stratus]

hm

ok weird

revert the settings

[languid vector]

Both are installed in legacy I think

[boreal stratus]

revert as the were in first pic, then boot linux up, and open Disks app in accessories, and click hdd and show

[languid vector]

Scroll to the top to see my screenshots

[boreal stratus]

(well leave quick boot off)

but the rest put back how they were

[boreal stratus]

oh right

[languid vector]

Btw loto told me to do this. How do I do it

[boreal stratus]

hang on.

[languid vector]

Yessir

[boreal stratus]

what lot said is correct, basically what I said, however this case seems different

boot up to mint

[languid vector]

im in mint

[boreal stratus]

click p2, then click play button

if error, click the gear, and choose repair filesystem

after repair, click play button to mount, ensure windows core files are all intact

[languid vector]

mounted

[boreal stratus]

then open linux terminal, and do sudo update-grub

then reboot and see if u get grub menu with 2 OS

[humble oracle]

if theres only mint and advanced options in grub, check advanced

[languid vector]

a second, let me try

It did say that it found win 10

[languid vector]

But rebooting auto logged in into mint

[humble oracle]

from mint

can you do

lemme see where it is

[boreal stratus]

np just need to unhide the grub menu now

[humble oracle]

@boreal stratus do you know the dir of grub config

[boreal stratus]

etc/default/

[humble oracle]

you got it

[boreal stratus]

the mint online manual shows how

[humble oracle]

mint does hide grub

[languid vector]

What do I do

[boreal stratus]

https://linuxmint-user-guide.readthedocs.io/en/latest/grub.html

[languid vector]

Okay thanks

[boreal stratus]

not usually

[languid vector]

Let me see, I'll let u guys know if this doesn't work

[humble oracle]

I found out what grub is for the first tiem when I switched to debian from mint :D

[boreal stratus]

unless it didnt probe in the installer, and thought it was the only OS, and u have this situation

but the manual shows how to do

[humble oracle]

can you send a screenshot of

"sudo nano /etc/default/grub"

this thing

[boreal stratus]

as per manual: sudo nano /etc/default/grub.d/90_custom.cfg to edit

then ctrl-o to save, enter, ctrl-x to exit

and the rest it says

[humble oracle]

[languid vector]

I don't know what it means

[humble oracle]

one sec

[humble oracle]

can't you just comment out the style hidden line?

[boreal stratus]

idk i would do as it says

in the custom file

not the original grub file

[languid vector]

I don't understand the guide

[humble oracle]

"
hidden: When set to hidden, GRUB will not display the boot menu by default. Instead, it will boot the default entry automatically after the specified timeout period (defined by GRUB_TIMEOUT). This setting is commonly used for systems that are intended to boot automatically without needing user interaction, but still want to provide the option to access the GRUB menu if needed."

[languid vector]

What do I do?

[humble oracle]

okay let's try this

[boreal stratus]

To make it visible, as root, add these lines to /etc/default/grub.d/90_custom.cfg

[humble oracle]

go here

I think that adding one # is easier

[boreal stratus]

;

[languid vector]

Wait I'm so confused. One at a time

[boreal stratus]

u cant just uncomment it

[humble oracle]

if that doesnt work open the thing I told you and put a # in front of GRUB_TIMEOUT_STYLE

CTRL O then ENTER
CTRL X

[boreal stratus]

^^ that wont work.

[humble oracle]

i added it to my config lemme reboot and test

[boreal stratus]

if u insist on editing grub file directly, instead of the custom90 file, then:

hidden must say menu

and timeout can be but to 5 (seconds) if dont need so long

[languid vector]

How do I change this

[humble oracle]

yep grub was gone

do what i said it will fix it

just sudo update-grub after

[boreal stratus]

u already opened that file with sudo right?

[humble oracle]

sudo nano /etc/default/grub

[languid vector]

I typed it in the terminal. The menu appeared. Now what do I do

[humble oracle]

is it this menu?

[boreal stratus]

its a text editor

[languid vector]

Yes

[humble oracle]

yes you are in "notepad"

[languid vector]

lol

[humble oracle]

go in front of the GRUB_TIMEOUT_STYLE line and add a #

[boreal stratus]

these to lines

[humble oracle]

should be like this

[boreal stratus]

it must say menu

[humble oracle]

timeout can stay

leave time out to 10 thats how long you got to pick windows or mint before it defaults to mint

10 seconds

after that:
CTRL O, enter
CTRL X

after that restart your pc and pick windows from the menu

WAIT

also do sudo update-grub after CTRL X

[languid vector]

Oh praise the lord it worked

[humble oracle]

great

[languid vector]

How do I set it to open up windows by default though? Instead of mint

[boreal stratus]

keep fast startup off in Windows from now on, to prevent interference

[humble oracle]

btw thanks I was wondering how mint hid it's grub

I wanted to do it on my debian

[languid vector]

I had it off before I installed mint

[humble oracle]

grub default = 0, change it to 1

was windows the second thing in the menu?

sudo nano /etc/default/grub

[languid vector]

Nah, I think mint with compatibility or something similar was in second

[humble oracle]

change grub defai;t to 2 then

[languid vector]

Okey sor

[boreal stratus]

second thing would have been mint advanced

[languid vector]

Yes it was that

[boreal stratus]

0, 1, 2

[humble oracle]

CTRL O, enter, CTRL X, sudo update-grub

reboot

[boreal stratus]

number 2, (the third entry) would likely be windows

[languid vector]

Okay how do I switch keyboard input method

[humble oracle]

what's that?

[languid vector]

I can't find # on this

[boreal stratus]

check setting in mint for input method

[humble oracle]

SHIFT 3?

[languid vector]

I press shift + 3

It gives me £ sign

[boreal stratus]

if ur using some kind of chinese keybd maybe

[humble oracle]

weird

[languid vector]

I selected UK English

[boreal stratus]

or change Keyboard

[humble oracle]

open start menu and type "keyboard"

[boreal stratus]

in the settings

[humble oracle]

select US english

[languid vector]

One second

[humble oracle]

UK people are weird

[languid vector]

Oke thanks again

Y'all are the best

[humble oracle]

https://tenor.com/view/nerd-nerd-cat-cat-nerd-glasses-pointing-out-gif-7875205738553206546

Actually I'm the best

[boreal stratus]

you're welcome. please use the dots menu at top and add the Solved green tag

[errant berry]

tldr user made a mistake when custom partitioning and made a mess on his drive, seems like just running update-grub and unhiding the boot menu fixed

[languid vector]

idk if you remember but i changed the timeout to 2 seconds for the grub menu but it's still 10 seconds long. do i have to make any more changes?

[humble oracle]

sudo update-grub

[languid vector]

i have to do this after i change the grub file?

[humble oracle]

you always do that after any change to the grub file

[languid vector]

ohh

thanks again