Lexar flash drive dead?

[Ian Smith]

In freebsd-questions Digest, Vol 637, Issue 3, Message: 20
On Tue, 16 Aug 2016 21:31:12 -040 Jonathan Stewart <jonathan at kc8onw.net> wrote:

 > (Please CC me as I'm not subscribed right now)

And please cc me on any reply; I take the -digest.

 > I have a Lexar USB3 128GB flash drive that has quit working. I get the 
 > following on the console and in dmesg when I plug the drive in, is there 
 > any hope other than a professional recovery company for this drive? On a 
 > Windows machine it does some kind of disconnect/reconnect loop but just 
 > triggers the text below on FreeBSD.

Have you tried it on other FreeBSD boxes too?

 > ugen1.3: <Lexar> at usbus1
 > umass0: <Lexar USB Flash Drive, class 0/0, rev 2.10/11.00, addr 3> on usbus1
 > umass0:  SCSI over Bulk-Only; quirks = 0x8100
 > umass0:9:0:-1: Attached to scbus9
 > da4 at umass-sim0 bus 0 scbus9 target 0 lun 0
 > da4: <Lexar USB Flash Drive 1100> Removable Direct Access SPC-4 SCSI device
 > da4: Serial Number AAUAYQ9QH3OH4ONS
 > da4: 40.000MB/s transfers
 > da4: 122104MB (250068992 512 byte sectors: 255H 63S/T 15566C)
 > da4: quirks=0x2<NO_6_BYTE>
 > (da4:umass-sim0:0:0:0): READ(10). CDB: 28 00 0e e7 bf fe 00 00 01 00
 > (da4:umass-sim0:0:0:0): CAM status: SCSI Status Error
 > (da4:umass-sim0:0:0:0): SCSI status: Check Condition
 > (da4:umass-sim0:0:0:0): SCSI sense: NOT READY asc:3a,0 (Medium not present)
 > (da4:umass-sim0:0:0:0): Error 6, Unretryable error
 > (da4:umass-sim0:0:0:0): READ(10). CDB: 28 00 0e e7 bf ff 00 00 01 00
 > (da4:umass-sim0:0:0:0): CAM status: SCSI Status Error
 > (da4:umass-sim0:0:0:0): SCSI status: Check Condition
 > (da4:umass-sim0:0:0:0): SCSI sense: NOT READY asc:3a,0 (Medium not present)
 > (da4:umass-sim0:0:0:0): Error 6, Unretryable error
 > (da4:umass-sim0:0:0:0): READ(10). CDB: 28 00 00 00 00 01 00 00 01 00
 > (da4:umass-sim0:0:0:0): CAM status: SCSI Status Error
 > (da4:umass-sim0:0:0:0): SCSI status: Check Condition
 > (da4:umass-sim0:0:0:0): SCSI sense: NOT READY asc:3a,0 (Medium not present)
 > (da4:umass-sim0:0:0:0): Error 6, Unretryable error

When that's finished logging, does /dev/da4 still exist?  If not, I 
don't know.  'Medium not present' looks pretty serious.

But if so, you may be able to recover most of its contents, less any bad 
blocks (which will be replaced by NUL bytes), using something like:

  # dd if=/dev/da4 of=recovered.img conv=noerror,sync bs=512

A blocksize of 512 bytes may be overkill, and it will be slow, but will 
ensure that any recoverable sectors are recovered.  Being flash, actual 
block size is almost certainly larger, but 512 is safest, and what the 
drive reported above.

If that does work, you may be able to mount it with something like:
  # unit=`mdconfig -f recovered.img`
  # mount -t $whatevertypeitis /dev/${unit} /mnt 

Depending on whether filesystem metadata is good enough to use ..

Some others here will know more, and/or know better, I expect.

cheers, Ian