> grub> device (hd0) /dev/mapper/hpt37x_ehgjaggaf > grub> device (hd0,5) /dev/mapper/hpt37x_ehgjaggaf6 > grub> root (hd0,5)/boot > Attempt to open drive 0x80 (/dev/mapper/hpt37x_ehgjaggaf6) > Error 5: Partition table invalid or corrupt > grub> root (hd0,5)/boot > Attempt to open drive 0x80 (/dev/mapper/hpt37x_ehgjaggaf6) > Error 5: Partition table invalid or corrupt Think it tries to read a partition table out of a logical partition, humn... No idea where to look for this bug; hints appreciated. > grub> root (hd0,5)/boot > Attempt to open drive 0x80 (/dev/mapper/hpt37x_ehgjaggaf) > Error 18: Selected cylinder exceeds maximum supported by BIOS Examining further, GRUB thinks the disk has only 4999680 sectors. It corresponds to about 2.441 MB, while the disk is really about 160.000 MB. Looking through the source code, the above sector value is some insane default in GRUB. The code tries to use 3 different ways of getting the sector count: 1.) ioctl(fd, HDIO_GETGEO) call in lib/device.c Fails with error -1. Documentation/hdio.txt from kernel sources has this to say with regards to that function: "Not particularly useful with modern disk drives, whose geometry is a polite fiction anyway. " 2.) fstat (fd, &st) Fails with error 0. No idea what this should do :-). 3.) ioctl(fd, BLKGETSIZE) call in lib/device.c This works for device-mapped devices! Seems to be a widely used function, there's even a 64-bit version. Unfortunately, GRUB only attempts this approach after having *successfully* retrieved cylinder, head and sector values through HDIO_GETGEO. I've gone ahead and solved my problems myself; the attached patch fixes GRUB 0.96 to work correctly (at least for me) with device-mapped devices. This is my first hack ever with anything Linux-ie. So go ahead and flame at will :-).
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GNU GRUB version 0.96 (640K lower / 3072K upper memory) grub> device (hd0) /dev/mapper/hpt37x_ehgjaggaf grub> root (hd0,5) Attempt to open drive 0x80 (/dev/mapper/hpt37x_ehgjaggaf) Filesystem type is reiserfs, partition type 0x83 grub>