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Can't access bios after installing linux on TOSHIBA satellite P875

Hey,
My bios was in uefi mode when I was using windows 10. I wanted to dual boot with linux so to let my pc recognize my bootable linux usb I changed it to crm. I installed GRUB2 boot loader on the same partition as my linux installation. Since I installed linux no manufacturing screen gets displayed so I can not access my bios. YES I am sure that the key to enter my bios is F12. So beceause I can't access my bios to change to UEFI I am locked out of my windows partition.
I would like to remove linux and GRUB but I would be more then happy if I could be able to boot into windows again.
All help is appreciated.

Might start with sudo efibootmgr command and see what is listed.

Guess it is possible that you have too many entries in efi, some hibernate issue.

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My bios was in uefi mode when I was using windows 10. I wanted to dual boot with linux so to let my pc recognize my bootable linux usb I changed it to crm.

This likely wasn't necessary at all as many if not most linux iso's are dual mode in that they can boot in EFI mode or legacy mode. They have two bootloaders in the iso, usually isolinux for legacy BIOS and have an /EFI directory with grubx64.efi and even grubia32.efi for any 32-bit EFI systems. The following is from a Fedora 28 iso.

Code:

$ sudo mount -t iso9660 F28-KDE-x86_64-20180603-Live.iso /mnt/iso

mount: /dev/loop0 is write-protected, mounting read-only

$ cd /mnt/iso/

[iso]

01:59 PM $ ls

EFI  Fedora-Legal-README.txt  images  isolinux  LICENSE  LiveOS  TRANS.TBL

[andrew@server47 iso]

$ cd EFI

[EFI]

$ ll

total 2

drwxrwxr-x 3 root root 2048 Jun  2 22:22 BOOT

[EFI]

$ cd BOOT/

[BOOT]

$ ll

total 6309

-rw-r--r-- 1 root root    1210 Jun  2 22:22 BOOT.conf

-rwx------ 1 root root 1044208 Mar  6 14:23 BOOTIA32.EFI

-rwx------ 1 root root 1293304 Mar  6 14:23 BOOTX64.EFI

drwxrwxr-x 2 root root    2048 Jun  2 22:22 fonts

-rw-r--r-- 1 root root    1210 Jun  2 22:22 grub.cfg

-rwx------ 1 root root  766280 Apr 23 15:31 grubia32.efi

-rwx------ 1 root root 1075016 Apr 23 15:31 grubx64.efi

-rwx------ 1 root root 1009888 Mar  6 14:23 mmia32.efi

-rwx------ 1 root root 1263400 Mar  6 14:23 mmx64.efi

-r--r--r-- 1 root root    1995 Jun  2 22:22 TRANS.TBL

Which Linux distribution did you install as you never mentioned it ?

Debian 9 is installed I tried installing in efi but it wouldn't recognize my bootable USB.

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Might start with sudo efibootmgr command and see what is listed.

If they installed their Linux in legacy mode efibootmgr likely won't be installed. They would have to install it first.

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Debian 9 is installed I tried installing in efi but it wouldn't recognize my bootable USB.

You could look inside the .iso file as I showed with mount -t iso9660 iso-file /mnt/iso to see if it has an /EFI directory and grubx64.efi.

I found this page on Debian UEFI support.

https://wiki.debian.org/UEFI

Quote:

Booting from removable media

If there are no boot variables pointing to a bootloader program in the ESP, or if the user has told the system appropriately, it will look for bootloaders in certain specific paths too. On each device, it will look for FAT32 filesystems. Within each of those, it will look for a specifically-named bootloader file, again with a different name per architecture:

Architecture

Path

amd64 \EFI\boot\bootx64.efi
i386 \EFI\boot\bootia32.efi
arm64 \EFI\boot\bootaa64.efi

The different names are deliberate - it allows for one disk or CD to contain boot files for multiple architectures with no clashes.

On Debian installation media, each of these files is again a copy of grub-efi with sufficient built-in code and configuration to find the rest of the system from there.

Therefore there should be a grub efi bootloader at \EFI\boot\bootx64.efi.

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Debian 9 is installed I tried installing in efi but it wouldn't recognize my bootable USB.

If you used Rufus to create that stick you may need to do it over selecting binary copy. Not selecting binary copy will allow Rufus to alter the .iso before writing it to the stick.

Atm I am not really interested in if I could have installed it in efi or not. First of all I want to get back in my bios, anybody knows how? Is tried installing efibootmgr but it asks me to put in my cdrom, is a USB also possible?

Entering BIOS is usually not F12. Usually it's DEL or F1 or F2 or F10. Try holding down one of these keys as soon as you year a speaker beep if it ever beeps. If it doesn't beep, then hold the key down as soon as you turn on the power.

No f key works no matter how long I press or how fast I press.

Are you using a USB keyboard? If yes, can you substitute a PS/2 keyboard? Or, a different keyboard?

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Have you considered simply unplugging your SSD/HDD ? If your BIOS has no drive to boot it may display its interface. Power down the laptop, open it up and disconnect the drive. When powered up again it may display the BIOS interface.

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Are you using a USB keyboard? If yes, can you substitute a PS/2 keyboard? Or, a different keyboard?

The OP is using a laptop computer a Toshiba Satellite P875 which of course has its built-in keyboard.

Unplugging HDD worked I changed back to EFI and windows booted perfectly fine. Thanks all