Arch Linux

thinkanish

Member

Registered: 2012-08-12

Posts: 39

[Solved] Theoritical Query- in Arch wiki Dual boot with windows topic.

Hello,

When I was going through the "Dual boot with Windows" topic in Arch wiki, I came across this paragraph :

Bootloader UEFI vs BIOS limitations :
Most of the linux bootloaders installed for one firmware type cannot launch or chainload bootloaders of the other firmware type. That is, if Arch is installed in UEFI/GPT or UEFI/MBR mode in one disk and Windows is installed in BIOS/MBR mode in another disk, the UEFI bootloader used by Arch cannot chainload the BIOS installed Windows in the other disk. Similarly if Arch is installed in BIOS/MBR or BIOS/GPT mode in one disk and Windows is installed in UEFI/GPT in another disk , the BIOS bootloader used by Arch cannot chainload UEFI installed Windows in the other disk

Here, I got confused because, as I understand, UEFI and BIOS are inherent to the motherboard of a system. So, in the above paragraph, it says that Arch installed in UEFI cannot load Windows installed in BIOS in another disk - Here it appears that UEFI and BIOS are parameters concerning the disk (HDD i suppose). Is this related to a network loading or am I missing something here?

Thanks.

Last edited by thinkanish (2022-04-25 15:23:50)

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,285

Re: [Solved] Theoritical Query- in Arch wiki Dual boot with windows topic.

No it's concerning the way you configured your UEFI to boot your system. Many UEFI still have a BIOS compatibility mode for older systems (think old linux kernels or Windows Vista and earlier). If you boot your installation ISO using that instead of the EFI standard you won't be able to set up a EFI bootloader and if you continue through with that your UEFI will boot your bootloader with the BIOS standard (which in turn can't go "back" to EFI  and thus not load EFI binaries). On proper EFI systems you will have an internal bootloader of the mainboard which will be able to boot one or the other anyway, but e.g. if you setup GRUB in BIOS mode for any reason then GRUB will not be able to have an entry for booting Windows. But in any case unless you have a very good reason for it, opt for an EFI install, pay attention that the entry you are booting into from the ISO is denoted with UEFI or similar.

Last edited by V1del (2022-04-25 10:14:50)

thinkanish

Member

Registered: 2012-08-12

Posts: 39

Re: [Solved] Theoritical Query- in Arch wiki Dual boot with windows topic.

Thanks much for you reply.

I have no experience working with UEFI systems since my newest personal laptop was purchased in 2009 which has BIOS by the way.

V1del

Forum Moderator

Registered: 2012-10-16

Posts: 25,285

Re: [Solved] Theoritical Query- in Arch wiki Dual boot with windows topic.

So is this just a theorethical question? Assuming you eventually acquire a new enough system you should in general simply opt for setting everything up in EFI mode, there are many limitations to traditional BIOS that make using modern systems somewhat harder/cumbersome if at all still possible.

If you do consider the question to be sufficiently answered, please mark the topic as [SOLVED] by editing the title in your first post, or ask any follow up questions if something's still unclear.

Last edited by V1del (2022-04-25 10:25:38)

thinkanish

Member

Registered: 2012-08-12

Posts: 39

Re: [Solved] Theoritical Query- in Arch wiki Dual boot with windows topic.

Hello,

Yes. I understand. I don't have a new system. But if I get one, I remember to keep the UEFI in the EFI mode always.

Thank you very much for your time and suggestions. I will mark it solved.