I've had similar things happen on my current build-box, but just wrote it off to a weird bios thing. Tweaking the MBR never occurred to me that I can recall.
I'll see if it is still happening to me. .... Ken On Fri, Nov 01, 2013 at 09:09:21PM +0100, Stefan Sperling wrote: > I have run into a small issue with an x130e thinkpad and a 4GB USB stick. > > After running fdisk -i on the USB stick, having the stick inserted > at power-on prevents the laptop from booting. It gets stuck with a > black screen, before even showing the first 'Thinkpad' logo screen > where I can enter the BIOS by pressing F1. Eventually the system > resets automatically, but then hangs again as before. > > When I remove the stick while the system hangs, the system instantly > resumes booting. I can reinsert the stick and 'reboot' from the boot > loader, and the system comes up properly. 'machine diskinfo' shows > this for the stick: > > Disk BIOS Type Cyls Heads Secs Flags Checksum > hd1 0x81 label 492 255 63 0x0 0xd1aa95e2 > > This is the partition table created by fdisk -i: > > Disk: sd1 geometry: 491/255/63 [7892992 Sectors] > Offset: 0 Signature: 0xAA55 > Starting Ending LBA Info: > #: id C H S - C H S [ start: size ] > ------------------------------------------------------------------------------- > 0: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > *3: A6 0 1 2 - 490 254 63 [ 64: 7887851 ] OpenBSD > > Disabling USB boot support in the BIOS fixes the issue but makes > it impossible to use the USB stick as keydisk since the stick > doesn't show up in 'machine diskinfo' anymore. > > Zeroing the first MB of the stick also fixes the issue. > 'machine diskinfo' now shows: > > Disk BIOS Type Cyls Heads Secs Flags Checksum > hd1 0x81 label 490 255 63 0x0 > > The problem also goes away if I manually create a partition table with > 'fdisk -e -c 490 -h 255 -s 63 sd1' that looks as follows: > > Disk: sd1 geometry: 490/255/63 [7871850 Sectors] > Offset: 0 Signature: 0x0 > Starting Ending LBA Info: > #: id C H S - C H S [ start: size ] > ------------------------------------------------------------------------------- > 0: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 3: A6 0 1 2 - 489 254 63 [ 64: 7871786 ] OpenBSD > > 'machine diskinfo' for that is: > Disk BIOS Type Cyls Heads Secs Flags Checksum > hd1 0x81 label 490 255 63 0x0 0x2c0f040e > > I bought 3 of these USB sticks and ran into this problem with 2 of them. > I then unwrapped the third one from the packaging and tested it unmodified. > The system boots fine and 'machine diskinfo' shows: > > Disk BIOS Type Cyls Heads Secs Flags Checksum > hd1 0x81 label 985 128 63 0x0 0xb919a6ea > > The partition table looks like this in fdisk: > > Disk: sd1 geometry: 491/255/63 [7892992 Sectors] > Offset: 0 Signature: 0xAA55 > Starting Ending LBA Info: > #: id C H S - C H S [ start: size ] > ------------------------------------------------------------------------------- > *0: 0C 0 1 1 - 491 80 37 [ 63: 7892929 ] Win95 > FAT32L > 1: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 2: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > 3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused > > Can anyone explain this problem? > > Is it a BIOS/UEFI firmware bug? > Is it an incompability between OpenBSD's fdisk and the BIOS that can > happen due to diferences in disk geometry detection heuristics? > Is it a bug in OpenBSD"s fdisk?
