Adam Wilson a écrit : > > There is a potential problem also where modern machines (with UEFI > boot) fail to install off USB without UEFI, meaning that if you want a > UEFI-free install, you have to use optical media.
I have a rather old (~2007) UEFI motherboard which does the opposite : its UEFI firmware lacks USB and AHCI drivers so it is impossible to boot in UEFI mode from a USB device or from a SATA drive in AHCI mode. > This happened to me > on an ASUS UX51vz with UEFI- with Debian 7 d-i, inserting an optical > disc would provide the option to either boot the disk with UEFI or > without it, Was this option displayed in the regular firmware boot menu or in a different menu ? > while inserting a USB would only allow UEFI boot from the > flash drive, and not legacy booting, even with Launch CSM enabled. Do you mean the the firmware boot menu only displayed one option (EFI mode) for the USB device ? Did you try to boot a non-EFI capable USB boot media, such as a Debian live image or a Debian installation image with the EFI partition deleted ? > So while using Debian 7, I just had to use optical media to install > Debian sans UEFI (which I always do- call it nostalgia, but I like the > simplicity of MBR and four primary partitions rather than the > unfamiliar layers of GPT/UEFI related cruft). Note that UEFI is not tied to GPT and vice versa. I happily use GPT on legacy systems when I need many partitions and LVM is not an option. Extended and logical partitions just suck. > Booting off USB (forced > to use UEFI) would simply result in a black screen after selecting > "Install". I have seen this display problem with the EFI framebuffer driver in Wheezy's kernel on some machines. Installing with a serial console worked. > Debian 8, however, seems to have solved this problem. Indeed, the kernel EFI framebuffer driver in Jessie's driver seems to have been improved. > USB can still > only be booted from UEFI, but newer d-i means that installation now > proceeds as normal until the point at which UEFI yes/no (force/leave) > selection is reached I don't remember seeing this option in Jessie's installer when booted in EFI mode. How is it labeled exactly ? At what stage is it proposed ?
