dd aplied to dev USB before connect corrupt /dev/sdX and dont work
Device nodes like /dev/sd*
only show up in /dev after the device is connected, not before. (Also, they aren't called "registers".) So when you ran dd of=/dev/sdb
it didn't actually touch any device – instead, since the output file didn't exist, dd
created a new file by that name.
$ sudo dd if=archlinux-2016.04.01-dual.iso of=/dev/sdc 1482752+0 records in 1482752+0 records out 759169024 bytes (759 MB, 724 MiB) copied, 0.941926 s, 806 MB/s $ ls -l /dev/sd* brw-rw---- 1 root disk 8, 0 Jun 15 08:54 /dev/sda brw-rw---- 1 root disk 8, 16 Jun 15 14:14 /dev/sdb -rw-r--r-- 1 root root 724M Jun 15 15:06 /dev/sdc
So there's really nothing that could have been "corrupted", and nothing that makes sense to "repair" or ddrescue. You simply have a huge file named /dev/sdb
, and because it exists, the kernel can't create a real device node there.
(The write speed makes perfect sense – /dev
is stored in RAM, so you just copied the image from RAM, where it was cached, back to RAM, where /dev lives.)
Delete /dev/sdb
and reconnect the device, and the real device node should reappear.