Root issue: grub ignore protective GPT record if that record is not the first one in MBR. Need to correct: If protective GPT record appears on any place in MBR - grub must consider system as GPT.
My system is Ubuntu and package I using is grub-pc 1.99-21ubuntu3.
I trust that my error is not distributive specific
I have hybrid GPT/MBR. Hybrid MBR contains protective record 0xEE but that record is NOT first. Here is output of gdisk (hybrid MBR): Number Boot Start Sector End Sector Status Code
1 468992 101480447 primary 0x07 2 234375168 234569727 primary 0xEF 3 * 550782882 574927413 primary 0x83 4 1 468991 primary 0xEE
gdisk (GPT): Number Start (sector) End (sector) Size Code Name 1 2048 206847 100.0 MiB EF00 EFI system partition 2 206848 468991 128.0 MiB 0C01 Microsoft reserved part
3 468992 101480447 48.2 GiB 0700 win7 4 101480448 138344447 17.6 GiB AF00 other 5 390625280 527343615 65.2 GiB 8301 copyfilesWIN7 6 527343616 550780927 11.2 GiB AF00 backupfile
7 581042176 625141759 21.0 GiB 2700 Samsung_diag 8 138344448 234375167 45.8 GiB 0700 DATA 11 574927414 581042175 2.9 GiB 8200 12 234375168 234569727 95.0 MiB EF02 grub
13 550782882 574927413 11.5 GiB 0700 linux
After that it result in such errors: address@hidden:~# grub-install /dev/sda /usr/sbin/grub-setup: warn: This msdos-style partition label has no post-MBR gap; embedding won't be possible!.
/usr/sbin/grub-setup: warn: Embedding is not possible. GRUB can only be installed in this setup by using blocklists. However, blocklists are UNRELIABLE and their use is discouraged.. /usr/sbin/grub-setup: error: will not proceed with blocklists.
invoking grub-mkconfig manually gives: address@hidden:~# grub-mkconfig -o test.conf Generating grub.cfg ... Found linux image: /boot/vmlinuz-3.2.0-24-generic Found initrd image: /boot/initrd.img-3.2.0-24-generic
Found linux image: /boot/vmlinuz-3.0.0-19-generic Found initrd image: /boot/initrd.img-3.0.0-19-generic Found linux image: /boot/vmlinuz-2.6.38-14-generic Found initrd image: /boot/initrd.img-2.6.38-14-generic
Found linux image: /boot/vmlinuz-2.6.38-8-generic Found initrd image: /boot/initrd.img-2.6.38-8-generic Found memtest86+ image: /boot/memtest86+.bin grub-probe: error: cannot find a GRUB drive for /dev/sda4. Check your device.map.
grub-probe: error: cannot find a GRUB drive for /dev/sda5. Check your device.map. grub-probe: error: cannot find a GRUB drive for /dev/sda6. Check your device.map. grub-probe: error: cannot find a GRUB drive for /dev/sda7. Check your device.map.
done
I have tried diferent approach - was removed hybrid MBR (retained only protective record). After that grub-install succeed. After that I have created hybrid MBR (the same as above). But after reboot I have got "grub rescue" prompt and error: no such partition.