Hi Felix, in short answer is during installation process yast2-bootloader propose everything the best it can. On running system it respects current configuration and do proposal only if broken configuration is detected and user confirm that he wants new proposal. So in your case I would say that it does not use write to MBR box because "/etc/default/grub_installdevice" does not contain line with "generic_mbr". Josef On 1/1/25 13:52, Felix Miata wrote:
Is it identical whether run from an installed system, or during the installation process? The reason I ask is that looking at <https://doc.opensuse.org/documentation/leap/reference/html/book-reference/cha-grub2.html> I find no reference to a BIOS/Grub boot partition for Grub use on a legacy system with GPT partitioning. It makes me suspect there's a separate step required for populating the BIOS/Grub partition that only the installer handles.
I did a migration to a new disk GPT partitioned from an MBR original (with 42 partitions & roughly 30 distros installed), first partitioning, then formatting, then copying content with rsync, then adjusting fstabs. I've never tried using GPT on a legacy system previously. I booted the GPT disk's TW from the old disk's legacy Grub, installed rpm Grub2 and its deps, then ran yast2 bootloader, expecting yast2 to do the whole job, but the result is the BIOS reports no bootable device found. During yast2, on the first tab, because I found no reference to a BIOS/Grub partition, I checked only the write to partition and set active flag boxes.
Was not checking the write to MBR box a mistake? Looking at the BIOS/Grub partition in a binary editor, it's all nulls. :( Looking at the MBR, I see what looks like DOS Windows compatible code normally used on all my MBR disks, which my partitioner usually puts there when it creates the first partition on a new or wiped disk. :p
Answer: it was a mistake, but how could I have known? I booted from Grub legacy again, then reran yast2 bootloader, checked the write generic code to MBR box, OK'd, rebooted, and all is now good WRT booting TW from new GPT SSD in 2009 Core2Duo PC. :)
# parted /dev/sdb print Model: ATA KINGSTON RBU-SNS (scsi) Disk /dev/sdb: 256GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags:
Number Start End Size File system Name Flags 1 1049kB 263MB 262MB k256p01 DOS C: reservation msftdata 2 263MB 599MB 336MB k256p02 reserved for ESP msftdata 3 599MB 1018MB 419MB ext2 k256p03 res legacy_boot 4 1018MB 1019MB 1049kB k256p04 BIOS Boot (noEFI) bios_grub 5 1019MB 1020MB 1049kB k256p05 DOS dummy msftdata 6 1020MB 1285MB 264MB k256p06 DOS E: reservation msftdata 7 1285MB 4402MB 3117MB linux-swap(v1) k256p07 swapper swap ... 9 11.1GB 15.7GB 4614MB ext4 k256p09 /home ... 12 43.4GB 47.6GB 4194MB ext4 k256p12 /usr/local ... 23 115GB 121GB 6711MB ext4 k256p23 tumbleweed ... # Note: I believe parted reports ext2 for #3 because I omitted the journal in running mkfs.ext4.