On Sun 29 Dec 2024 at 01:20:17 (+0100), Rafał Lichwała wrote: > > I plan to switch completely from Windows 11 to Debian on my laptop, > but as a first step I'd like to configure double-boot setup to give it > a try, look around and check if all hardware works fine under Debian. > > Current state: > Dell laptop (one NVMe disk only) with Windows 11 onboard. > Windows starts in UEFI mode (Secure Boot ON). > Already resized main partition to make space for Debian. > So currently there are the following partitions on disk: > > 100MB, FAT32, GPT (EFI System Partition) > 16MB, Other, GPT (Reserved Partition) > 300GB, NTFS, GPT (Data Partition) (Main C: disk visible under Win11) > 168GB, free space, ready to have ~150GB for Debian and 16GB for swap > 880MB, NTFS, GPT (Recovery Partition)
> Third try: > Boot in Legacy Mode (so Secure Boot is OFF). > Debian Trixie can see my laptop disk properly, so installation is > successful, but... > It cannot see my Windows 11 installation when trying to > install/configure/prepare GRUB. It doesn't need to. Switch to UEFI mode, and the ESP will boot into Windows. > At this step I decided to NOT install GRUB on my main disk to NOT > loose access to my Windows 11 system. If you booted in Legacy Mode, then Grub will install itself into the protective MBR. If it then asks about installing “an extra copy of the EFI version of the GRUB boot loader to a fallback location, the "removable media path"”, say No. > (but Trixie says that it's possible to restore access by manual > configuration of GRUB later on - I'm not sure...) Yes, that's on the same screen as I just mentioned. But you say No, so you don't touch that fallback in the ESP.¹ However, when you install Grub in Legacy Mode on a GPT disk, you ought to make a small partition with code EF02, a BIOS Boot Partition. 4MB will do, and doesn't mess up alignments. Grub puts its core.img there. It's not essential: Grub can put core.img into your linux partition using blocklists, but this technique is fragile. It would do for the time being while you're trying out Debian in the presence of Windows. When you eventually wipe Windows, you'll be installing in, or converting to, UEFI mode anyway. > Main goal: > To have both current Windows 11 and new Debian Trixie available in > GRUB and properly bootable. Both would be bootable, with the current setting of UEFI or Legacy Mode determining which one boots this time around. BTW I'd recommend bookworm to start with, as others have. ¹ I've had that screen come up on machines that predate EFI, where the first sentence is obviously nonsense. Cheers, David.
