Dear Greg, and everyone else thanks for the detailed responses. By UEFI versus Legacy Boot you mean things that are determined in BIOS settings correct?
Yes I am running in UEFI mode, but the partitioning is MBR and not GPT. Is this a problem? Which is preferred when? Why would legacy boot be preferred? Greg Wooledge <g...@wooledge.org>, 11 Haz 2021 Cum, 22:07 tarihinde şunu yazdı: > On Fri, Jun 11, 2021 at 09:38:37PM +0300, Semih Ozlem wrote: > > I reinstalled the system, including an efi partition (500MiB) and the > > problem was fixed. > > This suggests that you booted the installer in UEFI mode, rather than in > Legacy mode. If you boot the installer in UEFI mode, you are expected > to install a system that will boot in UEFI mode, which means it needs an > EFI partition (and GPT disk label). > > If you wanted to create an install that would boot in Legacy mode, you > need to boot the installer in Legacy mode first. > > (Or maybe there's something you can do in Expert mode to work around it; > I don't know. At a bare minimum, you'd need to switch which of the > GRUB packages gets installed -- grub-pc vs. grub-efi.) > > > How to check where grub is installed? And what is a friendly guide to > > learning about grub? > > GRUB should be installed on the *disk* (not on a partition) that you > intend to boot. > > There are two different GRUB packages: grub-efi for UEFI booting, and > grub-pc for Legacy (BIOS) booting. The mode in which you booted the > installer determines which of these gets installed at the end of the > installation. > > Legacy (BIOS) booting is the old quasi-standard. It's been around since > the 1980s. In this paradigm, the boot loader code is installed to > something called the "master boot record" (MBR) which is really just the > first few hundred bytes of the disk. Some space is left unpartitioned at > the start of the disk to make room for this. Much hand-waving is involved. > > UEFI booting is the new standard. It's been around for several years > now, so it's fairly widespread, but not quite ubiquitous. UEFI booting > requires a GPT disk label (partition table type), and one of the partitions > on the disk must be an EFI partition. This is a FAT-type file system which > contains programs used by the boot loader. > > A lot of machine (probably most machines made today) can boot in either of > these two modes, because not everyone has moved over to the new standard > yet. Older machines will only support Legacy booting. A few newer > machines > may only support UEFI booting. > > Secure Boot (Microsoft's attempt to stop you from using Linux) relies on > UEFI booting, and therefore this was one of the driving forces behind it, > but not the *only* driving force. If your machine doesn't use Secure Boot, > don't worry about it. It won't affect you. > > Of course, this is not everything there is to know about UEFI and Legacy > booting, but it might be enough for most purposes, especially if you just > want to install and run Debian, and don't particularly care about the > inner workings. > > Next, the care and feeding of GRUB on an installed Debian system: > > In the /boot/grub directory there's a file named grub.cfg. This is the > menu that GRUB reads from disk when you boot. It's generated > automatically every time you do certain things (like installing a new > kernel package). If at any time you'd like to regenerate this menu > (because you changed something yourself), you run this command: > > update-grub > > You should not edit grub.cfg directly, because your changes will be > overwritten eventually. > > If you'd like to change how the menu operates, there are a few pieces > you need to know about. > > The first is /etc/default/grub which is a file containing lines of shell > code. It's only supposed to contain variable definitions, and these > variables affect the overall menu, or they affect every menu entry. > You can change these variables (e.g. if you'd like the menu timeout to > be a bit longer because your monitor takes several seconds to switch > modes, or if you'd like to remove the "quiet" flag so that you can see > more details of what's happening). > > Individual menu entries are generated by shell code fragments in the > /etc/grub.d/ directory. If you'd like to add a menu entry of your own, > you can create a new file in this directory. You'll need some expertise > for this. If you'd like to customize the generated segments of the GRUB > menu, you might consider editing one of the existing files in this > directory, but make sure you have a backup, and a means of booting in > rescue mode, first. This is not something you want to break, especially > if it's a remote system. > >
