Re: DD bs=4M option on USB mem-stick creates false format
- Date: Mon, 27 Mar 2017 00:12:03 +0200
- From: "Thomas Schmitt" <scdbackup@xxxxxxx>
- Subject: Re: DD bs=4M option on USB mem-stick creates false format
> > /sbin/fdisk -l /dev/sdb
> Disk /dev/sdb: 7.2 GiB, 7751073792 bytes, 15138816 sectors
Is this about the correct size of the stick ?
> Units: sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
Looks like a normal block size for USB sticks and conventional disks.
> Device Boot Start End Sectors Size Id Type
> /dev/sdb1 * 64 1374207 1374144 671M 0 Empty
> /dev/sdb2 1297212 1298619 1408 704K ef EFI (FAT-12/16/32)
This is the MBR partition table. You may use fdisk to add a partition.
(Let's hope it will not hate that sdb2 is located inside sdb1.)
> echo 2 | sudo /sbin/gdisk -l /dev/sdb
> Warning! Main partition table overlaps the first partition by 64 blocks!
> You will need to delete this partition or resize it in another utility.
gdisk definitively hates the start of the outer partition.
But starting at block 64 would mean that it would not be mountable.
> Number Start (sector) End (sector) Size Code Name
> 2 1297212 1298619 704.0 KiB 0700 ISOHybrid1
The EFI partition is more to its taste.
As said, the GPT of an ISO with "mjg" layout is quite useless
and i'd zeroize its header block at block address 1.
Have a nice day :)