On 2018-05-14 01:21, songbird wrote: > Pascal Hambourg wrote: > ... >> I agree with the author. If you want to keep the existing EFI Windows >> installation and have a convenient dual boot with GRUB, you'll have to >> set up your favourite distribution to boot in EFI mode. If you want to >> go back to legacy boot, including for Windows, you'll have to >> repartition the disk to MSDOS format and reinstall Windows. > all i know is that if your bios doesn't boot in > UEFI mode and you don't know anything about what this > means you can end up installing Debian without UEFI > support and then it can be rather fun to get it back. > > i managed to have grub do an install to a stable > partition without UEFI and i messed up the testing > setup i had. it took me some while to figure out > what went wrong and how to fix it. if you don't > really understand grub rescue commands and there > isn't a working system you can use to connect and > find help for the commands you need to enter it's > very frustrating. > > the Debian UEFI pages helped a great deal but > there were other things i had to figure out coming in > cold to UEFI. > > how to create a /boot/efi partition, what goes in > it, mounting it, clearing and putting in new efibootmgr > entries, etc. > > refind was useful and at least it does what i expect > it to do. grub, i dislike how it assumed things i > didn't want to do. alas, i didn't know how different > UEFI was from bios mode. > > i still haven't redone my efibootmgr entries but > refind doesn't care, i can create custom entries in > that config file and they work that is all i really > need at this point. > > > songbird > Hmm, do you have any useful references?
I got a new Dell computer, shrunk the existing partitions down and successfully installed grub2 and got a windows10/Linux multi boot using grub. Then later I tried to upgrade my Linux and soon found that I was getting error messages about grub not being able to find necessary features on the boot device. I tried to rebuild it with a clean install of Windows 10, reasoning that if I could get it back to the original configuration, I could repeat the original exercise. But alas, no, it remains stubbornly unable to install grub2 alongside the windows bootloader. I got it to a state where I could use the BIOS POST boot screen to choose a boot option, but this wasn't the original successful arrangement where grub offered me the Linux/windows loader choice. I gave up, wiped windows and went through with a clean Linux install. I don't really want windows that much, but it irks me that I haven't been able to fathom out how to return to the original state in which it was shipped. Your words hint at many things I became vaguely aware of but totally failed to grasp. The other posters to this thread have at least reassured me that it isn't easy or trivial to get right. -- Chris