On Tuesday, May 10, 2011 05:13:46 am Camaleón wrote: > On Mon, 09 May 2011 13:21:20 -0700, Peter Bonucci wrote: > > On Monday, May 09, 2011 10:25:44 am Camaleón wrote: > >> > Booting a USB drive when the drive and computer don't cooperate is an > >> > old problem. People solved it under Debian years ago. I just don't > >> > know how they solved it and search engines didn't help. > >> > >> There shouldn't be any mistery for this. If the BIOS is capable of > >> booting from a USB device but the drive where Debian has been installed > >> is bypassed by the BIOS, I would check that: > >> > >> 1/ GRUB is installed into the MBR of the USB disk. > > > > I believe I did this while installing Debian on the USB drive. How can > > I verify it? > > Last time I needed to know where was GRUB installed I used: > > dd if=/dev/sda bs=512 count=1 | od -a | grep G > > (where "sda" is the disk of which MBR is to be queried) > > >> 2/ Partition where "/boot" is installed is marked with the bootable > >> flag (if there is no dedicated partition for "/boot", then "/" should > >> be the one to be marked). > > > > Already done. The "/" directory is marked boot. > > Fine. As Arno suggests this is not usually needed but is better to do it, > just in case. > > >> 3/ The system can be properly booted from an external source (i.e., > >> using a LiveCD of SuperGrubDisk). > > > > The laptop boots from its own hard disk. > > Yep, but as GRUB2 is being bypassed, we need to know if there is any > problem with GRUB2, so we are checking if it's installed in the MBR and > also if it's properly installed on the partition. > > > Under SuperGrubDisk, "List devices/partitions", Grub doesn't see the USB > > drive. None of the other options boot the drive. > > > > Selecting the experimental USB support doesn't seem to change anything. > > How is that? It should be accesible by SGD :-? > > http://www.supergrubdisk.org/wiki/USB_Boot > > But I'm starting to think the problem may be on the Western Digital USB > drive, as you said you were only facing problems with this concrete USB > disk... Look, it seems there is one report on WD forums: > > How to boot linux from My passport > http://community.wdc.com/t5/My-Passport-for-PC/How-to-boot-linux-from-My-pa > ssport/td-p/74214 > > Greetings,
This is where I am now: As Larry suggested, I removed the virtual CD from the drive. I reinstalled Debian on the USB drive. SuperGrubDisk v1.98s1 does not see the drive, or any of 5 flash drives. SuperGrubDisk v0.9977 does see the drive. It reports the drive it as hd1 with a size of 0 K It does see the 5 flash drives and reports the correct sizes. file -s /dev/sdb returns: /dev/sdb: x86 boot sector; partition 1: ID=0x83, active, starthead 32, startsector 2048, 488280064 sectors; partition 2: ID=0x82, starthead 254, startsector 488282112, 19531776 sectors; partition 3: ID=0x7, starthead 254, startsector 507813888, 468889600 sectors, code offset 0x63 dd if=/dev/sdb ibs=512 count=1 | od -a | grep G returns: 1+0 records in 1+0 records out 512 bytes (512 B) copied, 7.8496e-05 s, 6.5 MB/s 0000260 eot @ bs D del ht D stx G eot dle nul f vt rs \ 0000300 | f ht \ bs f vt rs ` | f ht \ ff G D 0000600 G R U B sp nul G e o m nul H a r d sp Fdisk -l says: Disk /dev/sdb: 500 GB, 500072348160 bytes 255 heads, 63 sectors/track, 60797 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks Id System /dev/sdb1 * 1 30395 244147806 83 Linux Warning: Partition 1 does not end on cylinder boundary. /dev/sdb2 30395 31610 9759487 82 Linux swap Warning: Partition 2 does not end on cylinder boundary. /dev/sdb3 31610 60797 234444577 7 HPFS/NTFS Warning: Partition 3 does not end on cylinder boundary. The USB Legacy option is enabled in the BIOS. If grub is in the MBR for the USB drive shouldn't I be able to boot it? Do you understand what is going on here? Peter -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/201105110054.04101.peter.bonu...@verizon.net
