What about the board’s like mine which are newer and have CSM. Even though they are UEFI they provide support for legacy boot so maybe it’s possible even on these newer boards that have this?
Edit: After reading this I don’t know exactly how it is working. Maybe not how I think?
A UEFI system can boot only from a GPT disk, not MBR. A BIOS system can boot only from an MBR disk and not GPT, which is why you can’t take an OS disk from a BIOS system and put it in a UEFI system and expect the system to boot.
Most UEFI motherboards come with a Compatibility Support Module (CSM), which is enabled by default. It makes the motherboard actually look like a BIOS system, allowing it to boot from NTFS and MBR disk, but you lose the UEFI features and are essentially just using BIOS. If you want to run your system as UEFI, you need to disable the CSM via the motherboard’s interface before you install Windows.
Your UEFI system can boot only from a device that has an EFI boot loader, so after the CSM has been disabled, the only boot devices that are listed will be UEFI aware.
After Windows is installed, msinfo32 (System Information) will show the BIOS mode as UEFI, not legacy.
So if you have CSM enabled and you install Windows 10 supposedly you cannot disable it after. It has to be done before installation. According to what I read. I know on my current installation with EndeavourOS it doesn’t seem to matter if I turn it on or off in UEFi and I have Windows 10 installed on another drive?
I think that info you quoted is in regard to Windows only. You can mess up (I mean mix and match) much more simply on Linux! Even with CDM turned on (on some boards at least) UEFI still works - you just have to make sure that you are using it when you expect!) rEFInd - which is an UEFI specialist - can still recognize and successfully an MBR WIndows setup alongside any UEFI setups present as well.
Still a good idea to stick to UEFI if possible - there are so many bad things you can avoid that way!
Well I guess I’m just wondering if you have UEFI set to CSM could you install both an MBR installation and a UEFI installation and boot with the grub fix that @manuel has done? That’s what I was getting at.
To my knowledge, using UEFI is a better idea on machines that support both.
UEFI is a newer specification, and it should support e.g. larger disks (if I remember correctly).
And gpt is also better (=simpler to the user) than msdos partition table, because partitioning is more straightforward on gpt disks.
These questions come up typically when
dual-booting or multi-booting
adding another disk to a machine
so if you are planning those scenarios, it is good to know about the booting alternatives and disk properties.
Anyway, best to use whatever works for you and your hardware.
Is a seperate boot partition (mounted at /boot) needed in addition to ESP (mounted at /boot/efi)?
edit
So my question actually is: will this work in mix legacy-uefi dualboot system where the uefi system is set up with only an ESP mounted at /boot/efi and a root partition. mounted at /?
I have run into this scenario sort of? I’m not entirely sure. On another system which has EndeavourOS Xfce installed they tried to install MX linux and the ESP selection is greyed out. I tried setting UEFI only and made no difference. Couldn’t figure out how to install it in UEFI. Previously i have updated the UEFI Bios on it after installing EndeavourOS. So i ended up installing MX linux in MBR mode on the other drive and they just have to select that drive on boot with the F11 key. I can’t figure out why the ESP won’t show. Tried numerous live ISO. Funny thing is i installed MX linux using my system in UEFI mode to an External usb drive and it boots fine in UEFI off of that other system. But when you try to install it the ESP selection is greyed out. Both boards are MSI X570. Mine is the MPG X570 gaming plus and the other one is the X570-Pro-A. It’s wierd. I never tried installing MX on it originally when i installed EndeavourOS which is installed in UEFI. So I’m going to have to try some other live ISO’s of say PopsOS or something just to see but it’s odd. My original plan was to boot them using rEFInd but it doesn’t work because it wants’ to boot the image or the efi grub. It picks it up in rEFInd and i can hide the icons but when there is a kernel update they show up again. So i might just remove rEFInd and just keep booting with the F11 key anyway so i don’t have to contend with that all the time.
