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Dual boot BIOS mode
Posted: 2021/07/24 18:24:21
by lattimro
Hi everyone,
I have installed CentOS 8 in BIOS mode also Windows 10 is in BIOS mode and the os-prober does not see anything (I do not know if it have an output on BIOS mode).
I check centos for BIOS mode:
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[root@localhost brad]# ls /sys/firmware/
acpi dmi memmap qemu_fw_cfg
[root@localhost brad]# efibootmgr -v
EFI variables are not supported on this system.
[root@localhost brad]# efivar -l
efivar: error listing variables: Function not implemented
[root@localhost brad]# os-prober
[root@localhost brad]#
The workaround was to add to /etc/grub.d/40_custom the lines:
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menuentry "Windows 10" {
set root=(hd0,1)
chainloader +1
}
and regenerate the grub menu:
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grub2-mkconfig --output=/boot/grub2/grub.cfg
Now dual boot works fine but I am wondering if this is the correct mode to enable dual boot. Thanks!!!
Re: Dual boot BIOS mode
Posted: 2021/07/24 20:25:45
by owl102
lattimro wrote: ↑2021/07/24 18:24:21
os-prober does not see anything (I do not know if it have an output on BIOS mode).
Yes, it should have an output. Is the package ntfs-3g installed? If not then please install it and try "os-prober" again.
Re: Dual boot BIOS mode
Posted: 2021/07/25 01:11:05
by lattimro
Thank you so much, I installed and works fine!
to be honest, I read other posts and they also said ntfs-3g is required but I thought it will be for read/write Windows NTFS. As I did not have this purpose I ignored it.
ntfs-3g is an NTFS driver, which can create, remove, rename, move files, directories, hard links, and streams; it can read and write files, including streams, sparse files and transparently compressed files; it can handle special files like symbolic links, devices, and FIFOs; moreover it provides standard management of file ownership and permissions, including POSIX ACLs.
It comes in two variants ntfs-3g and lowntfs-3g with a few differences mentioned below in relevant options descriptions.
The volume to be mounted can be either a block device or an image file.
Re: Dual boot BIOS mode
Posted: 2021/07/25 07:39:56
by owl102
lattimro wrote: ↑2021/07/25 01:11:05
to be honest, I read other posts and the also said ntfs-3g is required but I thought it will be for read/write Windows NTFS.
You are totally correct but in BIOS mode os-prober needs to read NTFS partitions to take a look if there is a MS-Windows installed onto it, therefore ntfs-3g is required here.
Re: Dual boot BIOS mode
Posted: 2021/07/26 02:58:04
by lattimro
absolutely, totally agree! Thank you so much, much appreciated.
Re: Dual boot BIOS mode
Posted: 2021/08/01 13:28:08
by kraomohsin75
Hi there,
What is the purpose of "chainloader +1"
why windows entry in grub is different with linux distro entry?
many thanks,
rao
Re: Dual boot BIOS mode
Posted: 2021/08/01 13:46:47
by jlehtone
kraomohsin75 wrote: ↑2021/08/01 13:28:08
What is the purpose of "chainloader +1"
why windows entry in grub is different with linux distro entry?
GRUB does not have specific support for MS Windows. The chain loading is a more generic method.
https://www.gnu.org/software/grub/manua ... hainloader
https://www.gnu.org/software/grub/manua ... ading.html