Package: cdimage.debian.org Severity: important Tags: newcomer Dear Maintainers,
It appears that the Debian 8.0 "Jessie" ISO release uses a GRUB binary that doesn't embed the 'part_gpt' GRUB module. Because of this, if you happen to copy the "Jessie" ISO content onto a FAT32 drive (eg: USB Flash Drive) that was partitioned using GPT, you will end up with the GRUB rescue prompt when booting on a UEFI system, as GRUB will not be able to locate the installation files on the GPT drive. Note that this is only an issue if you copy content into an installation media that is GPT: If you use 'dd' to create the installation media from the ISOHybrid, or copy the content to a FAT32 drive that uses the MBR partition scheme, then the problem does not occur. Looking at the GRUB EFI binary's strings from the ISO, it seems that 'part_gpt' was not embedded, which in turn prevents the embedded 'grub.cfg' from locating the '/.disk/info' marker during the search for the root media, as it cannot access GPT volumes. I'm hoping that the GRUB EFI binary can be modified for next ISO release to include 'part_gpt', as this should prevent this issue. The expectation is that Windows users, who may have heard that simply copying the Debian ISO content on a FAT32 drive should work with UEFI systems (and who prefer using that method because they find DD/image tools a bit daunting), will encounter this issue if they happen to copy the ISO data onto a drive that was partitioned in GPT mode. This is also a problem for Windows USB installation tools, such as Rufus, if you set the USB partition scheme to GPT, as it also uses the ISO -> FAT32 copy method. * What led up to the situation? Trying to install Debian 8.0 in UEFI mode on an intel NUC (D54250WYK), after copying the whole ISO content to an USB drive with a single GPT/FAT32 partition. * What exactly did you do (or not do) that was effective (or ineffective)? Tried to use the GRUB rescue prompt, but was unable access the USB disk. After recreating the USB installation media using an MBR/FAT32 partition, I found that it worked, which demonstrates that this is a GPT vs MBR partition scheme issue. Finally, looking at the GRUB binary on the Release ISO, it seems pretty clear that the 'part_gpt' module is missing, which I believe is required, even in UEFI mode, to access GPT partitioned drives. Regards, /Pete -- System Information: Debian Release: 8.1 APT prefers stable APT policy: (500, 'stable') Architecture: amd64 (x86_64) Kernel: Linux 3.16.0-4-amd64 (SMP w/2 CPU cores) Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
