Indeed, this test was bad... But the same occurs with an offset of 63 sectors :(
Same with fdisk: fdisk: 1> edit 3 Starting Ending LBA Info: #: id C H S - C H S [ start: size ] ------------------------------------------------------------------------ 3: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused Partition id ('0' to disable) [0 - FF]: [0] (? for help) A6 Do you wish to edit in CHS mode? [n] offset: [0] 63 size: [0] 488392002 fdisk:*1> q Writing current MBR to disk. bash-3.2# fdisk wd1 Disk: wd1 geometry: 30515/255/63 [490234752 Sectors] Offset: 0 Signature: 0x100 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: 00 0 0 0 - 0 0 0 [ 0: 0 ] unused Xavier -- Secret hacker rule #11: hackers read manuals. On Wed, 2 Jan 2008, Nick Holland wrote: > Good thing OpenBSD only runs on one platform and one type of computer, > eh? > > Xavier Mertens wrote: > .. > > > > 16 partitions: > > # size offset fstype [fsize bsize cpg] > > a: 48195 0 4.2BSD 2048 16384 16 > > c: 490234752 0 unused 0 0 > > Assuming this is i386 (what people usually assume when they don't > bother to show dmesg or even mention platform), you need a one > cylinder offset on your 'a' partition (or more accurately, your > first partition. TYPICALLY, that's 63 sectors, but not always). > What you have here clobbers your MBR, which holds your (now hosed) > fdisk partitions. > > see faq4.html. > > Nick.